Service Engine Soon Light/ Cylinder Misfire

[texjun99]

I have a 2001 Frontier (V4) with a recurring problem: the service engine soon light keeps coming on. I have seen similar posts with this same problem and have replaced the distributor cap, rotor, and spark plug wires. I have also tried Berryman's fuel treatment with no luck. Luckily, my next door neighbor is a mechanic and has been able to erase the codes after each attempt, but the light still comes on. I get really awful gas mileage and we still get a cylinder misfire code. In addition, the engine does run rough and have replaced the O2 sensor last year. Has anyone else had this problem? I've seen posts suggesting to replace the crank position sensor, or it may be a busted ring, or bad catalytic converter...

Ideas?? Anyone??

[scootek]

jump it. that will fix everything. if that doesnt work then launch it!!!

[XterraGuy]

What specific codes are you getting out of the computer? There are individual misfire codes, and multiple cylinder misfire codes.
And what's this V4 engine you speak of? :p

[HMD]

This all sounds very familiar.....how many miles on it?...Has it had the other tests done, like: compression, valve leakage, and timing? how about hooking it up to a scanner and check for any sensors out of range? If everything else is good, it may need injectors -- I just went through this on my 95 3.0L.

[Berg]

Before you do all that......clean your egr valve and egr passages.
What happens is that 2-3 passages get blocked off with carbon and throw excess heat into the cylinder and throws a misfire code.

misfire #4 ...

erase the code and clean and check egr