Cylinder 1/2 misfire - help please

2006 Tacoma 2.7L 160k miles

Hello all! Would love some advice please. CEL came on stating cylinder one and two misfire. Unsteady idle at times and the car loses power when I go over 50 which is when the CEL blinks. I replaced the two spark plugs and swapped the coil from 1/2 and 3/4. Light still came on after reset. I then took apart the fuel injectors and cleaned them thoroughly replacing the O-rings. Still no luck. Did a compression test with 1/3/4 at 150 and 2 at 130 which looks good. I'm stuck at this point. I was told that I can bring it to the dealership to get diagnosed to find out exactly what's going on. I called and they told me it would cost $450 just for the diagnosis. Can anyone give some advice? This is my DD and man it sucks not having it for work. On a budget as well so if I can do the work I definitely would. Never really done this type of work, but search and videos have been a great help. I'm thinking of replacing the fuel injectors at this point, but they are so expensive. TIA!!

 

Curious what codes you exactly got.

 

P0301 and P0302

 

Time for valve cover and spark plug tube gaskets. Then some new coils will perk the old girl right up. Good luck!

 

Hmm. Maybe a fuel pump filter clogged or the fuel pump slowly going bad? Inadequate fuel delivery, esp. at higher speeds / under load. Although that probably wouldn't cause rough idling & and flashing CELs at high loads/speeds, with normal operation between idle & 50mph... But remember that sometimes two symptoms (such as rough idle, and power loss above 50 mph) could be caused by 2 separate problems that aren't directly-related.

For example:
Maybe an EGR or EVAP valve malfunction is causing a loss of vacuum that makes the engine idle rough.
And then a weak fuel pump which only manifests under high loads (>50 mph,) leading to fuel starvation & knocking. Does the 2TR-FE have a balanced fuel delivery system, i.e. equal pressure delivered to both ends of the fuel rail? Or does it have a feed line at one end and a return line at the other end?

If the fuel rail doesn't have balanced fuel delivery, then cyl #1 and #2, fartherest away from the pump-side fuel line feed to the rail, might suffer from fuel starvation before cyl's 3 & 4. (I.e. a weak fuel pump might provide enough just enough fuel pressure to feed the #4 & #3 cylinder injectors at high demand, but not enough to keep the #2 & #1 injectors properly fed.)

This is a long shot, and I don't know the 2TR-FE engine well, but if I was doing it I would look at the fuel-rail connections & read up online to see if it's possible to reverse the fuel line connections to the fuel rail & see if that makes the problem move to cylinders 4 & 3. If that panned out it would almost certainly suggest a weak fuel pump or other fuel-supply restriction problem. YMMV & check carefully as I don't know if that would cause a hazardous condition. I don't think it would because aside from the injectors on the rail, the only other device there is the fuel pressure regulator, which I don't think should care whether the fuel is fed from one end of the rail, or the other.

Separately: be sure to clean & inspect MAF sensor, that's critical for ECU to determine & maintain proper fuel trims. Also check & replace engine air filter if needed. Easy & quick to do.

 

Start by swapping the coil packs from cylinders 1 & 2 to 3 & 4 and see if the code follows to those cylinders. That would indicate it’s coil related. You can do the same with the plugs to try and isolate the problem. I have seen both coils and plugs cause this problem

 

Thanks for the advice. Going to order some oem valve cover and spark plug gaskets to replace during the weekend. Anything else I should look for or replace while I have everything off? Thanks Steve!!

 

Great advice! I'll try the gaskets first and then work my way to the fuel pump if the CEL comes back on. Didn't think about the MAF sensor. I'll clean that while I'm changing the gaskets. Thanks!

I did that already when the light first came on. Swapped coils 1/2 with 3/4 and the codes did not follow. I changed out the spark plugs as well with no luck. Wish it would have been that easy.

 

Cylinder leak down test is where i would proceed then, that being the case

 

Before you do all that, check the #1 and 2 injectors are getting a signal. Check you're actually getting spark at the #1 and #2 coils . (In case you have a wiring issue caused by mice or corrosion)

 

No. I just returned from a 400 mile round trip and it runs f’n unbelievably strong. Let’s just do the gaskets, plugs (I used

$39 NGK 6619 Iridium Spark Plugs LFR6AIX-11 - 6 PCSNEW

NGK 6619) and Standard Ignition Blue Streak UF495 coils You’ve got this. Good luck!

 

Ended up taking it to the dealership to get diagnosed. Found that it needs a new head gasket. Cost for them is $7k. I know I can get it done for less then that but the worst news I could have gotten. What to do....

 

I wonder if @Torspd has an idea. Edit: is it drivable? Head gasket? I ain’t feeling it. Get it the f out of there. Have the vc gaskets been replaced? Coils?

 

It is definitely drivable. There is a rough idle when I first start it, but it's fine once I'm going. There was a handful of times when I went over 50 and the engine was rough. Then that went away and it's good at high speeds. Haven't replaced the vc and I know it's not the coils.

 

From the dealership

 

Ok. Get the fk out of there. Find a local shop to replace the vc and tube gaskets. Be ready to buy coils. Try MSD. Edit: and ya, I ain’t buyin’ what they’re sell in’

 

I see that the dealership mentioned that the coolant reservoir was empty and the radiator was low. Have you been going through coolant? I didn't see that mentioned in your initial post.

 

I topped it off about a year ago and it was fine. It was on low when they checked it.

 

You’ve got this. Ask me how I know. Why that dealership won’t fix it and get you on your way is fn unreal

 

I got quoted $3200 from a reputable shop for the head gasket and resurfacing the cylinder head. Sound like a good price? I can have them replace the gaskets as well. I would just hate to pay someone to change the gaskets and the problem to still appear to have to pay the 3200 again. Thanks everyone for your help. Losing sleep over this