Cole33

Before I start this, yes, I did search. I am just making this thread to maybe get some discussion on what may be wrong before I spend more hours working on it.

That being said, last Saturday I took my car on a 3 hour trip. Everything was just fine. When I went to start my car on Sunday, it was very hard to start. And once it started, it ran very very rough for about 3 minutes, and then ran perfectly fine. Car made it all the way home with no issues.

I took the car home last night and checked the plugs, coils and wires. On visual inspection, the plugs looked great, the wires seemed fine, and the coils had no spots on them to be observed. They all looked to be in good shape. The connection to the battery also was fine. I decided it might be a fuel injector problem, and decided to run a bottle of cleaner through it and drove it back to college.

Today it is still very hard to start. I thought that may be the starter going bad, but I don't think that is the problem since the engine runs very rough until the car warms up.

Car is a 2004 MT with around 119000 miles on it. CEL are P0300 and P0302, both misfire codes.

Any thoughts on what may cause this? I have a few spare coils laying around that I may try swapping out. But the engine does not misfire once it is warmed up, even when doing hard runs to 8 or 9K on highway onramps.

RX8Soldier

iTrader: (24)

test the plugs and coils to see if they work.
Is your car making any unusual noise? MAF/ESP sensors clean?

Cole33

Just cleaned the MAF yesterday, but did not check the ESP sensor.
I am just not sure it has to do with the coils or plugs since the car runs perfectly fine with no loss of power after it is warmed up.

RX8Soldier

iTrader: (24)

if your ecu is showing misfire codes, I'd trust that more than your gut.
https://www.rx8club.com/series-i-tech-garage-22/suffering-misfire-start-here-222280/
https://www.rx8club.com/series-i-do-yourself-forum-73/diy-testing-all-rx-8-coils-gm-ls2-yukon-coils-sparkplug-wires-222641/

Cole33

True, true. I can't argue with that, I just figured I would run it by more people than myself before I spend hours testing something that may or may not be the problem. Since I live up at college, it is a pain to have to drive 30 minutes home to work on my car, and like to be able to do it efficiently.