somlt1

iTrader: (1)

Please if anyone can help me i cant figure out the problem with my car. the story with it is that it started last august i took it around the block then pulled in the garage then it through a po300 misfire code and a po443 air evap system then i turned it off no more start. I did a fuel pressure test ended up with no pressure so i changed the pump and also swaped the opti with a freinds one that i knew was working now the car starts and idles and reves fine but the misfire code is still flashing after i erased it and ran the car again. could any one help me figure out wat could be causing the missfire codes to come up?

ss.slp.ls1

iTrader: (36)

P0300 is for a random/multiple cylinder misfire. You are going to have to cover all of the bases.

Plugs & Wires
Coil
Opti
ICM

Replace parts in the order, check all wiring to/from/in between. Good luck man.

somlt1

iTrader: (1)

thank you i appriciate the help ive change the opti the plug wires are brand new new coil the plugs got changed a year ago but i sprayed it when i went 2 the track the last time i gues that i may have burned a plug up. i dont know much about the icm is that a seperate ingnition computer cuz ive seen you guys use that term alot on here and i only know pcm but not icm thanks again for the info.

ss.slp.ls1

iTrader: (36)

ICM = ignition control module. It is a little chip looking like module that the coil bolts to and both are bolted to the driver side cylinder head.

96formulabird

Had same problem. my opti was only 10,000 miles old and had p0300 code. come to find out the plugs i put it (ngk tr55) i had broke the tips off a few and the car had a miss. well i when i just put my headers on i put e3 diamond fire plugs in and new plug wires and no more po300 code. i just have to get all the emissions codes tuned out. but those are the only codes i get now. i would recomend e3 diamond fire plugs. You dont need to gap them and i know a lot of people that run them in high horsepower cars and they say they are the best they have ever used. Just my 2 cents

somlt1

iTrader: (1)

thanks guys youve been alot of help im pretty sure its plugs when we ran the car the year before we sprayed it and it was breaking up at the top of the shifts because of the fuel pump i think i burned up a plug then. also when i started it today got alot of carbon smell to the exhaust, smelled real rich so ill try those plugs that you recamended thanks!