HELP! I give up.

***UPDATE***
So, I figured that the $13 coils might be the cheap way to go and maybe so but I put the three new coils that I ordered along with the one that I had ordered previously in bringing my total new coils to 4. I took it out on the interstate and still lacks power and misses when under a load at 70-80 mph. I said to myself that I should just eliminate the possibility completely that the coils are the issue so I ordered 6 brand new Denso coils. They came Saturday and I popped them in. No change . So to recap what I've done. Truck was running perfectly fine just prior to a rat chewing my knock sensor wire and throwing a code that put the truck in limp mode. I had to drive it that way for about 2 weeks before I could get the new wire and time to replace it. I replaced the wire which required me to remove the air Plenum, fuel injectors, intake manifold and cooling tubes that ran between the heads. When I put it all back together I used RTV on the NEW intake manifold gaskets just for added measure. All codes went away, but the truck missed under loads and also when cranking, sounds like it takes a minute to hit. Previously it would start up with a 1 second turn over of the key. So, Then I replaced all the injectors thinking that I might have a bad one. No change. Then I replaced all the plugs. nothing. Replaced all the coils. nothing. Cranked the engine and saturated the engine bay with propane to see if I had a vacuum leak somewhere. Nothing. Totally out of ideas. It sounds to me like a fuel delivery issue. I did have to unhook the fuel pressure regulator to get the fuel rail out of the way during my repair. When I get a chance I'll have to look and see if the oring might be pinched or not sealing properly. The phenomenon is only noticeable when I first crank the engine, gun it on pulling out or on the interstate at 70-80 mph. When I gun it pulling onto the highway it will start out and respond fine then act like it's starving. If I push the pedal all the way down it'll drop in low and accelerate fine but when it planes out it misses like it's starving for fuel or air. Help!!

 

Negative cable took off while doing this? Just wondering...... sounds like you've got experience

 

Yes, I removed my battery cable prior to doing this work. I always do when I'm unplugging components. I did perform the TPS exercise of pressing the accelerator pedal 100 times to set position.

I strongly feel like it is a fuel delivery problem. It idles perfect. It runs perfect on secondary roads unless I gun it when pulling out. If I gradually accelerate, it's fine. It does act up only SOMETIMES when I crank it up. It has to spin a little longer than usual before it starts. But this is only sometimes.

On another note: Not a Clemson fan but watched Trevor Lawrence all through high school, so I'll pull for them when their not playing the Dawgs.

 

Where did you buy your replacement injectors? There are big issues with counterfeit fuel injectors being crept into various supply chains, and I experienced this a few years ago with "factory new" injectors on my '03 Tacoma. Two dribbled under pressure, and caused intermittent long cranking time during startups.

Also, using silicon sealant on the intake was an error. Great way to suck a piece of RTV into the engine and cause problems. Did you tighten the bolts in proper sequence and spec with a torque wrench, or go by feel?

edit: have somebody watch your exhaust outlet when cranking after the truck has sat for a few hours, look for a puff of dark grey/black smoke. This indicates one or more cylinders flooded w/ gas.

 

I bought the injectors from Rock Auto. Could be an issue, but I didn't buy the cheapest ones and this was happening with the original ones. I agree on the RTV but I did this to try to alleviate the issue because I thought it was sucking air. I put a very thin coat on taking care not to get around any of the air intake holes. Problem was there prior to RTV so I know that's not what caused the issue.
I tightened the bolts from the inside out crossing patterns and repeating about three times. I could not find a tightening sequence online for my intake anywhere and I just tightened by feel. I don't have a torque wrench nor do I know the specs. I was thinking about 13 ft lbs. so I took care with my calibrated arm not to exceed that.

I will have someone take a look when I start it up.

All very good advice and I appreciate the feedback.

 

That would be a good place to start, along with anything else you may have disconnected along the way. I would also use something other than propane to look for vacuum leaks. My money is on the intake manifold leaking but not detected by the propane. You're supposed to use an unlit torch and point the gas right at suspected leak points. I would think that flooding the engine compartment with enough gas would be pretty hard to do - safely anyway

If it was my truck I would (1) buy a torque wrench (or rent one from the store); (2) buy new intake gaskets and install them without RTV.

 

sounds like an air leak from somewhere or shitty connections.

 

Thanks Harry! I can do that. It's easy enough to get to (Since I've done it enough) Do you think that the intake can start leaking when the engine reaches a higher temp? I would think that if it were leaking I would feel it on the lower speed roads as well. It runs great until I get it on the interstate. I'll probably do that and maybe invest in a torque wrench while I'm at it.

 

Air leak I agree with. Bad connections would throw a CEL wouldn't it? I'm going with air leak because it sounds like it sometimes when I start the engine and accelerate quickly.

 

Just ordered a torque wrench from Amazon. I'm assuming from my research that the torque spec for intake manifold bolts is 13 ft. lbs. I couldn't find a torque sequence so I use the inside out cross method. I also ordered a Chiltons manual so maybe it'll have what I need. I hope all this work won't be in vain. It'll be a wasted golf day.

 

Just as @Jubei71 said, sounds as if you know what you're doing. So don't take this the wrong way or think I'm being condescending... Have you checked the air filter element itself? Starving for air will have some of the conditions you detailed.
If you have mice eating wires, you may have mice building nests.
Simple enough to check and rule out. I suspect you already have, but I would be remiss not to mention it.

 

No offense taken. Any possibility could be the cause. I did check the air filter. I also took my leaf blower and back flushed the tube running into the quarter panel. I didn't have any evidence of a nest anywhere I looked. No collection of debris on the filter itself. I did catch the rat hiding out in my cabin air filter housing. I yanked his ass out by the tail and slammed him on the garage floor.

 

Everything you'll need to work on your engine can be found here: http://www.customtacos.com/tech.old/files/05FSM/repair.html

Torque spec for the intake manifold is 19 lb/ft and found on page EM-121 here: http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0070011.pdf

edit: also, I'd put your factory injectors back in while you have the intake manifold off. Seems like they were working correctly when you had the initial problem...one less variable in the troubleshoot. Consider sending them out to a reputable shop for cleaning and flow testing, e.g. cruzinperformance.com or witchhunter.com.

 

A few questions based on what you wrote: Have you checked the integrity of the knock sensor circuit from the repair you made to the ECU connector? Maybe that rat did more damage than you know. Could you have a cracked or loose spark plug? Have you checked the fuel pressure running and leak down? Could he have chewed coil or injector wiring causing an intermittent? Do you have any pending codes now? Can you get any short/long term fuel trim data now? That should show a lean condition being compensated for on one or both banks. I wonder what the effect of driving for two weeks in limp mode had on the ecu learning or did I misunderstand you. It seems like you missed something along the line and it would be wise to backtrack.

 

I'm just spitballing here, but how exactly did you repair the knock sensor wiring? I don't know off the top of my head how the knock sensors' signal works amd I'd think it would be increasing voltage/decreasing resistance when they sense a knock, but I'd almost wonder if they're falsely sensing a knock...

 

I'll try to answer the last three posts here.
Old fuel injectors were sent back for core charge, so I don't have them any more to install.
The knock sensor circuit is complete. I replaced the entire harness from the knock sensors back to the main harness. It's just a short jumper and not possible to hook up backwards. I inspected the wiring very closely and there were no signs of rat damage anywhere else. I'm not entirely sure how the knock sensor works either, but that is the only harness running between the heads where it was warm and cozy for the rat.
I have no pending codes whatsoever. I even had a mechanic hook it up to his computer and reset everything, even history. He said that the computer didn't show anything out of sorts.
I have replaced all the spark plugs. Original ones didn't look bad at all.
Unfortunately there isn't a Schrader valve on the fuel circuit to check fuel pressure on the Gen II's so I haven't checked the pressure.
You didn't misunderstand me, I did have to drive it in limp mode for a couple weeks, but most of that was on 2 lane roads no more that 50 mph. I wouldn't think that would have done any damage to anything and if it did I would surely be throwing some kind of code.

I lay in bed at night trying to think of what I might have missed. I've gone over everything I can think of. I will go back in this weekend and re-set and torque properly the intake manifold since I didn't have the necessary information before to torque. While I'm in there I will thoroughly backtrack and inspect everything. I'm really hoping that a leaking intake is the issue, a small air leak that is multiplied when it's under load and pulling more air and fuel.

Thanks guys! I appreciate all your input. If you guys can think of anything else, please don't hesitate. I have been working on my own vehicles all my life and have never had one in the shop. Not that I'm too proud, it's more of a challenge thing, but I'm almost at the end of my rope and considering dropping it off to someone with more diagnostic tools at their disposal than I have, but I would be pissed if they found something simple like a leaky intake or vacuum line. I would lose all faith in myself.

 

all vacuum lines are good with no cracks (there is a small vacuum line that goes into intake at the back that i missed once)? Spark plug gap? O-rings on injectors are good after install? Maybe TPS connector? I would probably backtrack and try to locate all lines and connectors to ensure you didnt miss anything. Ive worked on all of my vehicles my entire life and it is surprising how many things I miss, not to say that you are forgetful as I am though.

 

lol! Will, I'm getting older so, yeah I miss shit. I put it back together and went down the driveway and my damn brakes didn't work. I forgot to hook up the booster line. But I assure you, I have looked and looked and cannot find any thing amiss. I did see that line on the back of the intake. It was hooked up. I would LOVE to find a hose loose somewhere!! I don't think it's anything electrical because I don't get any codes at all. I would think an electrical disconnect of any kind would throw a code.

 

What was the code that was scanned originally and was the check engine light flashing or steady? It's hard to believe that the miss-fire you have does not set a check engine light. Miss fires that cause running issues that can affect the cat converters turn on the check engine light to protect the cats. That is the main purpose of OBDII systems. The check engine light is working now right? We know it was before. And a question, not to insult you in any way, do you have low ( not implying empty) fuel level in the truck right now, say more than 15% of capacity?

 

Troyken, I had a steady CEL with a PO333 code initially. The check engine light does work because I checked it by unplugging a wire to throw a code just to check. All codes were reset and nothing has come up since. No blinking or anything.
I have ran it both ways, empty and full. I filled it up this morning and had to take a little road trip this morning and it still did the same thing.
Can I ask why you think the fuel level might have an impact? Purge valve?