I just bought my girlfriend a 2002 Galant. It has a P0300 code for a random cylinder misfire. I know it is probably just plugs and wires, but I was wondering if anyone else has had this problem? Any solutions? And it is running pretty rough

 

It is the 3.0L btw. Last night I cleaned the throttle body, used some injector cleaner, new plugs and wires and still has not fixed it. I hear it could be the distributor cap and rotor. Any validity to this?

 

bump....

 

Did you check the Burn of the spark plug and did you adjust the valves on the cylinder head. you changed everything except the rotor and cap. why? you should have replaced everything.

You can buy Restore if you want. read the label well before putting RESTORE. you can buy those at any auto parts store and regap your spark plugs make sure it's correct.

 

I work for Chevrolet and dont know a lot about Mitsu. I did not adjust the valves is this something anyone can do? I went ahead and changed the cap and rotor. What exactly is a restore?

 

RESTORE is oil additives that cleans engine oil gunk or fuel residue.

It is like Z-max but cheaper price about $5.00 or more used that when you reach 65,000 miles and below 65 do not use it.

If you don't know how the adjust the valve ask your mechanic to adjust it for you. it is not easy,,, you really need a lot of tools. like gap tool for valves, etc etc.

(the electronic timing mechanism that restore the timing of the engine. it is a computer that you plug in but that's for hard core tuner to do.)

if you planning to gap your valves? I recommend also to replace the cylinder head gasket. it's the rubber gasket around the cylinder head your mechanic will know if it is broken or there should be oil leaking on the side of the engine if its broken.

Actually Chevy cars are more pain in the butt to fix.

If the rotors and cap DO NOT WORK. you must have a broken cylinder head. if that's the problem I recommend trading in the car.

Here are the scenario for OBD2 P0300
Fuel injectors, related wiring, sensors and computer issues
Running out of gas, or poor fuel quality
Evaporative emissions system (EVAP) concerns: fuel vapors leaking into engine
Incorrect Fuel Pressure
EGR system concerns: leaking EGR valve or restricted ports
Base engine concerns: low compression, valve train problems and timing issues
Ignition system concerns including, but not limited to:
Faulty spark plugs
Faulty coil or related wiring
Ignition module or related wiring issues
Ignition related sensor faults or wiring issues

Please find the old spark plugs. it will tell you which one cylinder is not working properly or try running the car a day and TAKE OUT THE NEW SPARK PLUG. check the burn of plugs You will see the difference.
just marked each plugs

next time do not reset the OBD2 resetting it you will never find the problem some mechanics has advance OBD2 reader that really point where the EXACT PROBLEM OR PROBLEMS ARE. those OBD2 computer cost around $5,000 for the high end ones.

 

Chevy is simple to me. These are just weird. Well if these cars can only run 100k that doesnt say much for Mitsu.

 

Basically if it doesnt fix it then it needs an engine?

 

When we replaced the plugs none of them were burnt up though. They looked worn and then we replaced them. We have checked since and it seems fine. The thing that is weird is that the SES light stays off until you get on the freeway. Makes me think its an injector. Once you get on the freeway it drives great. If it were an engine problem it would seem to give more problems

 

Okay. It must be the Fuel systems are clog.

Fuel Injected,Fuel filter etc etc all that must be check.

You already made a Major tune up on your car. Did you ever replace the oxygen sensors? if not that would cause the engine to misfire too

Check Fuel system and Oxygen sensors. YOU DO NOT NEED A NEW ENGINE as long the engine does not emit Black and white smoke or red.

For now as long the car does not stall on the road drive it. Buy a fuel additives that clean the fuel system it might help for a bit. ADD THIS BEFORE YOU HAVE A FULL TANK. try buying a different fuel brand. they might added water or a leak on the underground tank at the place you buy your fuel. I am just guessing but it might be the cause of the problem. The additives let the water evaporates faster on your fuel tank if it is contaminated.

Mitsubishi engine are durable as long you take care of them. my last Mitsu was 200,000 miles and I still traded it in for $1,500

You are basically just tuning your car for another 100,000 miles if you find that problem and solved it. your car will last another 100,000 miles