Need Direction from Tacoma Gods before going to the Stealership...

Hey everyone.
Really, really need some direction before going into the stealership with my problem. So if anyone can help me out by chimming in with regards to suggestions or thoughts I would appreciate it very much.
Ok... so not sure how to really lay it all out so I'll do it in this fashion:

* Bought the truck (2000 PreRunner no TRD Xtra-Cab, 4cyl., Automatic tranny, no modifications noted) 5 days ago with 196K miles and no mechanical/electrical issues showing.

* After putting in 1/2 a tank of Chevron 91 octane gas into it, 2 days and 155 miles later after purchase, CEL comes on.

* KEY NOTE: At about 130 miles after purchase I had pressure washed my engine. Engine ran fine afterwards and throughout the course of the continued.

* Had CEL diagnosed at local PepBoys within 10 minutes of CEL triggering on and it shot back the infamous PO420 code (infamous cause I've read and found this is a quite common bug with these Tacomas).

* Same evening disconnected the negative terminal on my battery and left it disconnected for over 3 hours. Upone connecting it back up again, I turned on the engine to make sure all was on the up and up. Everything OK so far.

* Morning after, I jump in the truck about to head out, turn the truck on and terrible, terrible sputtering effect which lasted a good 30 seconds before gradually starting to make signs of improvement. Afterwhich drove off and no problem with performance of engine.

* Throughout the day and throughout my intermittent stops here and there, OCCASIONALLY, when getting into the truck and attempting to turn on the engine, I would only get 1 crank as if when the battery fails or some electrical goes out. A second or two later, turn key again and engine turns on as usual with no signs of hesitation. I had also noted that NEVER did the clock reset, lights go out, or radio stations lost. I figured that would scratch out any concerns with battery (which happens to be new).

* 82 miles later after having disconnected the negative terminal on the battery for 3 hours, CEL comes back on.

* Truck seems to be a bit more shakier afterwards than before, but still ran somewhat reliably overall. At least for a local trip to run errands, freeway, and uphills.

* Today while driving on a lever area of the freeway at 65-70mph, I felt as if the truck was hesitating much like when you're running out of gas (not the case though cause I still had 1/4 showing on the gas gauge). I immediately exited on the next exit within 1/4 mile and pulled into a gas station. Everything seemed to have been fine now.

* Drove for about another 8 miles on street this time and the truck started hesitating really bad. CEL started flashing continuously. Drove back home, 2 miles later, and truck felt really weak and hesitant.

Whew! Ok with that said, what do you guys think could be going on? I check under the truck while running in hopes of finding some smoke from an exhaust leak somewhere but nothing seems to be going on. Though I had been told that the truck had undergone a tune-up recently, I checked the plugs to make sure they weren't needing replacement and they looked brand new indeed. However they did have a strong gas smell to them. Checked vacuum lines leisurely by tugging here and there to sense anything loose, but nothing. Also did give the engine bay a good sniff here and there while running in hopes of picking up a scent of air leak so to support an assumption of a vacuum leak or exhaust leak, but nothing again.

I know that once I go to the stealership the first thing they are going to want to target are replacement of the O2 sensors and/or the catalytic converter. Obviously the more expensive fix first. But in the past, I have found that many times it's not as bad as diagnostic codes might suggest or point out. In this case, CEL gives a pricy problem area. Example, I used to own a Lexus SC400 which suddenly developed similar symtoms to what I have going on now, but much, much worse hesitation and even gave off backfires. I barely made it out to the local Lexus dealership, had it diagnosed and they wanted a little over $2600 for some cats and o2 sensors. Went to a local Toyota/Lexus specialty shop, they laughed at the Lexus dealerships theory of repair and instead assured me it was a blown head gasket. Repair price was going to be high as well, but can't recall exact figure. All in all, I didn't have that kind of money and committed to neither. Two days later after tinkering here and there, jumping into Lexus forums and other manufacturers forums, googling this and that, I found my problem to be that I needed to replace 1 coil pack which I ended up buying off of eBay for $90 with shipping included. Screw off the old, screw on the new... and walla!!! Problem was solved and car ran as new!!!

Now back to my truck though, this time I'm at a loss cause it has only been such a short time I've had it and I really have no history with it to better pinpoint an area of concern so to start tackling that area of repairs.

Sorry for the lengthy post, and I promise to cut the post hear so to not overbore you guys.

Thanks in advance for your help, time and feedback.

 

Oh yeah, I forgot to mention that I read up that a flashing CEL is an indicator of a misfire, but if that's the case wouldn't the misfire continue to and through the course of time until fixed?

As for the PO420 code, would a faulty o2 sensor and/or catalytic converter really trigger such rough idle and hesitation and then allow it to clear up?

Finally if the pressure washing process got some water into one of the coil packs and/or spark plug cylinders, after all the driving and heat build up on the engine surface and compartment, would it have not been dried up by now? How long does it usually take for it to dry? I read another post on here where a member had the same shaky issue after pressure washing this engine, but by the next day on his way to or from work CEL and negative engine behavior were self-fixed.

Thanks again guys!!!

 

Bad Gas?

A faulty o2 sensor can cause issues due to the computer trying to compensate for the false readings from the bad sensor.

 

Sounds to me like bad gas as well. I just got my truck recently, so I'm not sure if this is the case, but some engines don't do well with 91 octane gas.

 

I replaced two Coil on Plugs for my friend that had the same problem and it fixed it up. He had detailed it and sprayed a bunch of water in the engine compartment. The water creeps up in the CoPs and messes them up. Also the rubber boots on his CoPs were cracked and not looking good.

His was acting the same, it would run ok sometimes till it was hot and it would get rough running.

I think the CoPs were around 70 bucks each. Kind of expensive, that will teach you a lesson to spray your motor down. LOL.

Anyways I would buy one and install it where the faulty one is. The code should indicate that. If it doesnt then you can troubleshoot which one it is by pulling the spark plug wire on one cylinder at a time and see if it runs worse or the same. When it runs the same with the one wire off, thats your bad coil.

 

I think my friends also had a P03** code also though. They both cleared up once the coil was replaced.

At any rate, the troubleshooting could prove or eliminate the possibility before you go to the dealer.

 

Long post.......drop the octane you using.....too much octane can result in what I believe is called pre-ignition.

 

My mom had the same problem with her '95 4runner right after washing the engine. Turned out one of the plugs wasn't sealed completely and water got in. The dealership changed out the plugs for her and it ran great after that. My brother still drives it and has had no problems. Your injectors might also need to be cleaned.

 

I don't agree with the "bad gas" diagnosis, only because it was 91 octane. I think bad gas would show up more if it were 87 octane (lower octane, more likely to run crappy). Could be a delayed effect of powerwashing the engine.... maybe water got into something. But unless it shorted or damaged something, it should have cleared up once the engine was good and hot.

I would more tend to agree with frog.... maybe add some 87 when the tank gets lower.

 

Ok, all I read was your code, and the flashing MIL at the end. A flashing MIL is almost always ignition related. It can flash when the A/F mixture isnt getting burned in the cylinder and gets pushed though the exhaust, then burns in the CAT, which makes it over heat and burns the CAT up. If your lights flashing DO NOT DRIVE IT. A FLASHING LIGHT MEANS SOMETHING WILL CAUSE DAMAGE IF DRIVEN.

 

Is the o2 sensor reasonably new?

Check for any pinched or burned electrical wiring especially around the egr valve.

Tap the mass air flow sensor (with a screwdriver)while the engine is running; is there a change in idle?

If there is good exhaust flow out the tailpipe it shouldn't be the cat.

 

Hey again everyone!

First off and most importantly, thanks to you all for the feedback, suggestions, and overall help. This forum really shows to have a great crowd of members!!!

So... here's the latest and greatest news on my situation. Earlier I had to go pick up a friend from work to take her home. Jumped in the truck, turn it on, shaky but at very minimal level. Got out to the streets and drove for about 1/4 mile when the hesitation and shaking starts acting up again.

Long story short, ended up putting another 3-4 miles approx. before having to stop at a local Toyota/Lexus specialty shop where I've been to before with my other cars and feel confident with the mechanic's assessment of repairs and quality of work. I had to stop there because truck could not go more than 15mph on flat surface it seemed, and to get anywhere from where I was at geographically would require to drive uphill and didn't want to run the risk of having it die out and then needing to tow and such. So I explained the situation to the mechanic/shop owner exactly as I had mentioned to you all in my previous and lengthy post. I ended leaving the truck with him for a CEL diagnosis, compression check, and overall assessment of the trucks symptoms. About 30 minutes later, he gives me a call back to give me some bad news... here it is:

Coil plug to cylinder #4 is possibly faulty according to his read out, but he wants to attempt air drying down into the cylinder chamber where the spark plug sits, and spray silicon (i think that's what he said) onto and into the coil plug so to absorb all if any moisture that could have triggered a faulty coil plug reading and ultimately produce a misfire on that cylinder number. After which he would then check it again overall to see if the trick worked. If not, then proceed from there with most likely replacing the coil plug.

Not bad so far, but wait there's more... the real bad stuff...

Upon preparing to do a compression check of all 4 cylinders, while attempting to remove spark plug in cylinder #2, he discovered that the spark plug is stuck onto the head it seems. With that said, he stated that he could make an effort to unscrew the spark plug with the required force in an attempt to remove it from the cylinder, but he is concerned that it could break and end up leaving the threaded part of the spark plug in the cylinder head. This would ultimately require opening up the engine, removing the foreign spark plug particles and putting it all back together again with any and all necessay repairs, resurfacing, rethreading, and/or adjustments needed. Total damage estimated just for this at about $3500 to $3700.

Last but not least, though it's bad, it just doesn't seem to match up too much in overall wallet damage to the possibility of breaking the spark plug in the cylinder head... my catalytic converter is bad.

So going back to the possibility of overhauling the engine and the cost factor. I questioned whether if instead of rebuilding the engine at that price, would it not be more cost effective for me to just swap out the engine per say to a V6 now that the expense of a swap could be justified as a better bargain? I know these engines come a dime a dozen for well under a grand. He said that HE could not do it because it is illegal for him to do so. So I wonder if maybe from a vendors prospective, he prefers not to swap for the purpose of a better days work financially speaking, or unless there really is quite a bit of hurdles and red tape to go through with state and/or federal authorities to make it all done right and not as he put it, "illegal"?

What you think?

Thanks again gang for the input!!!

PS: I'm in the state of California and regarding obstacles and red tape issues, I hear California is the strictest. Yet I see and hear of engine swaps from one engine size to another going on all the time.

 

Hey just something to add to the spark plug situation. I once had this problem with an 87' toyota PU that someone had tightened the plug way to hard. I broke the spark plug with the thread still in the head. So I tried getting an easy-out in there and cranking on it with no success. I took it to a local toyota shop and they tried the same with no success and charged $70 to get me no where, after driving it home on three cylinders and scratching my head I looked at my bill that the shop gave me and they charged me for an easy-out? I popped the hood and sure enough they broke their easy-out in the spark plug thread. So a $70 bill to make my situation worse. So this is what I did. I drilled it out with a cordless drill and the easy-out fell in my head along with mass amounts of metal shavings, I spent 2 hours with shop-vac and got the easy-out out along with 99% if not all the metal shavings out and got one of those sleeves that they sell at auto parts stores(I forget what they are called) and truck ran fine. Total cost: $70, a few beers, and a few angry niehbors who overheard the obscenities coming from under the hood. Oh and a few hours of stress, hope this helps with one of your problems

 

Yep, thought it sounded like the plug or coil. You could fix this yourself for a hell of lot less. If you let some kroil penetrant sit on the plug for a few days or so, you may be able to get it out without too much trouble. The prices he mentioned are crazy worst case scenario crap. That way you will be relieved when he gently places his hands on your shoulders and slips you a bill for only a measly 1200 bucks for a $70 CoP, $5 plug and 1/2hrs work.

The guys not giving you any breaks or perhaps that trustworthy from the sounds of it. Plugs strip or blow out plug threads from time to time, it stinks when it happens but its not the end of the world. You can find much cheaper repair shops than what this guy is stating.

I would fix the CoP/plug issue then drive it and see if the catalytic needs to be replaced right away. You can get an aftermarket one for much cheaper than what the dealer is offering.

By the way, if your going to need to take your truck to the dealer for any problems you have, you may want to get a vehicle with a warranty. It can get expensive to have a used vehicle and not be able to tool on it a bit.

 

By the way, an engine swap to a different size would be a nightmare. A recycler would have the same size motor that wouldnt be that big of a deal to swap out, but I really dont think its going to come to that.

 

And I believe in 85yote09taco post he is refering to a heli-coil insert. Its the most common fix to a blown out/stripped plug thread.

 

yup kinda what i was thinking...

i had a stuck plug on a civic once... bought the thing with 140k and looked like the stock plugs... well i used an impact with the pressure down and the light "impacting" for a good 10 minutes actually got the plug loose and it came out. the aluminum came with it but at least it didnt break... thats where the helicoil comes in handy

 

Yeow... so sorry to hear of all that trouble on a truck you've only had less than a week! Another option to reduce down-time with the truck is to buy a used or reman head for it, so it would be a straight-up swap. I'm surprised the mechanic didn't mention a heli-coil as an option. Most any decent shop can do that.

All this speculation and worrying is ASSUMING that the threads will strip out in the head though. Hope for the best and plan for the worst. I think I'd go ahead and tell the mechanic to pull the plug and see what happens.

 

Hey again everyone!!!
First off, thanks again to all you guys for your guidance and help with my situation. Your feedback and advice was greatly appreciated.

Now for the good news (at least for me it is)... and I promise to keep this REAL short. After some rust remover sprayed down into the spark plug cylinder and allowing a small puddle of this to sit overnight over the spark plug seating... the morning after with a minimal amount of effort, the troublesome spark plug easily turned. After which immediately tightend it back up, got the vacuum and sucked out the sitting puddle until pretty much dry, then went back in with the socket and turned the spark plug all the way out.

Needless to say, replaced all plugs with new ones.

As for the coil-on-plug that was faulty, well also with some the use of a blowdryer and some overnight airing out, it appears that the was not faulty after all, just had some moisture issues.

All in all... everything turned out to be A-OK with the exception of the infamous P0420 code which points at my catalytic converters it seems.

Thanks again everyone!!!