Celica Forums General Discussion Engine and Performance Cylinder 4 misfire 03 Celica

Changed coils and spark plugs. Check engine light went away but came back. Rough start, rough idling at times. Loss of power. How should I proceed?

Check fuel injectors, MAF sensor, vacuum lines, spark plug gap.

Hey all, new here with major issues. I am not very knowledgeable when it come to cars, but I am trying to learn. So I just bought 02 Celica GT manual transmission almost 2 weeks ago. During test drive ran great the next day I have all 4 cylinders misfire. I replaced all spark plugs still misfiring. Then I did a compression check: cylinder 1 about 90 psi, cylinder 2 and 3 about 150 and cylinder 4 was about 95-100 but the adaptor wasn’t installed all the way. When reinstalling the coil packs I swapped them around 4 to 1 and switched 2 and 3. I also did an engine restore. I reset the codes drove about 75 miles and then the codes came back with the exception of cylinder 2. Most recent I replaced the MAF sensor reset codes and drove almost 200 miles and the code just came back with the exception of cylinder 4. I also have a code for Evaporative Emissions System Incorrect. I am so lost on what to do. Unfortunately I don’t know any history on this car. I appreciate any help given.

Note: car take what I think is a bit longer than it should to start and my idle is a bit rough sometimes it bounces but just a little.

For the evap code, check and make sure your fuel lid is screwed on all the way. That can cause the code. If not that, look into a charcoal canister.

As for the misfire, that is less fun. Was your MAF sensor replaced with an OEM part? Make sure you used iridium plugs, make sure the plugs are gapped correctly. Try new coil packs.

Let me know about all this and I'll see if I can help.

Update. The car doesn’t start at all the EFI fuse is making a weird noise and vibrating. I can hear the spark plugs firing.

It was the injector, took me a bit since the seals and o-rings broke on the other 3 when pulled out. Now I have still a code for the catalytic converter which I will try to fix by cleaning the o2 sensors.

Check to see you didn't knock anything loose while working on it. I accidentally knocked off an air hose and the car was not working properly.

90 PSI is very low compression. Normally should be around 190- 200 PSI for the 2ZZ engine.

The engine would not start with any cylinder that low.

For P0420

Add an extension to the rear O2 sensor (after the CAT).

that shoudl fix the problem.

Low compression may be caused by carbon deposits in piston rings or valves.

Flushing the oil with engine cleaning chemicals woudl dissolve the deposits and help rings/valve seal tight therefore increasing compsression.

GUNK by Motor Medic ($4 Walmart) restored compression in my 2ZZ Cyl 1, making it run smooth and strong again.

Label says use 1 quart and idle 5 minutes, but I used half quart and idled 10. Dumped oil was thick and black like asphalt slurry. Flushed 2 or 3 times until oil is clear/brown and not black. That should improve your compression.

Change both of your o2 sensor all your fuel injectors plugs and coils.
I had the same issues with misfire codes. Went through the whole trouble shoot and finally after I changed them all the engine light went out and never came back on.