Toyota techs! Help needed!

I have been battling a cylinder 1 missfire in my truck for the passed month. I have tried everything so far and the check engine light still comes on. Here is what I have done to try and solve the problem

-New plug
-Swap coils
-New wires
-New injector
-Clean MAF
-New battery
-compression test wet and dry (good)



My truck idles at about 790-800 rpm. It shakes a little at idle. Runs good and does not "buck" or major misfire. But every time I scan the cylinder 1 misfire keeps showing up.

Any ideas?

 

Hmm no idea, you have done all that would more then likely fix that misfire problem(code) .
Subbing for answer/solution

 

Could the timing be off? Not sure if that would cause just one cylinder to miss fire or not.

 

mine does the same thing on the scanner...

 

FSM points at additional potential culprits:
- valve clearances
- ECM not sending the signal to the injector
- Engine coolant temp sensor (not sure why)
- low fuel pressure

 

If you are going to look at the fuel pump, check to see which cylinders get fuel first. If cyl 1 gets fuel before the others, you can rule that out. Also, you could try running a 1-heat range hotter spark plug in that cylinder to see if that makes a difference.

 

cylinder one gets fuel last on the 2.7L i would check fuel pressure

 

Today my battery light started flickering. I checked all my conenctions. So i went and bought a new alternator and put it in. I am wondering if my alternator was on its way out (bought it at a junk yard) and could have cause my cylinder 1 to missfire now it says (pending codes) on my scanner (before the new alternator. I cleared it and will see if it comes back

 

Which engine do you have? The 4 cyls fire the injectors two at a time (1&3 then 2&4). If a 6 cyl, they're all independent AFAIK. I don't see how an alternator could cause a misfire. you might want to check the F.I. harness and connector in addition to the fuel supply plumbing as already mentioned.

 

its the 6 banger I am going to keep an eye on it. what does your 6 cyl idle at? miens 700

 

beware of vacuum lines that are being pinched or are rotted out. could lead to misfire, also, fuel filter. the pump could be ww2 merlin powered but if its trying to suck through a pinhole its gonna "suck".

 

Clean out IAC valve. Check fuel pressure. Howbdid you check compression on cyl 1? Did you also check 2, which is right across from it?

 

Did every cyl. Dry 150 on every cyl and wet 180

 

i think my cyl 2 and 3 were misfiring about a year ago.. ended up getting a valve job after replacing all the stuff you have replaced. but mine was a 4cyl. i just recently took my throttle body off to find out that the reason i probably ended up needing a valve job is because there was so much carbon build up past the throttle body i couldn't believe it when i saw it. i plan on taking apart the whole intake manifold and cleaning as much as i can out of it. i read somewhere to soak a tshirt in carb cleaner over night and push it through each hole in the manifold and then hook the shirt up to a drill and spin the shirt for a minute or 2 in each hole. i just used some sea foam in my VAC line last night and it actually helped a lot with my lack of power & rough idle. the amount of smoke that came out was intense.

 

Could it be a maf sensor

 

Burnt exhaust valve?

 

I did a compression test. I got 150 psi dry and 180 wet

 

Still got the missfire I am leaning towards head gasket or ecu

 

do a cylinder leak down test...

 

How so you do that