Celica Forums General Discussion Exterior Check engine error code P0-300? help?

A friend of mine has an
AUTOMATIC
2001 CELICA GTS
w/ 32k miles

Her check engine light came on and coded a ( p0-300)...Misfiring cylinder...

She also had a cracked water pump, shortly after buying the car NEW!!!!

The Toyota dealership in our area replaced the water pump, Belt tensioner (because the water from the busted pump moistened the belts, causing them to squeek), and replaced the belt.

A month or two later her check engine light triped again, the misfiring problem had worsened... The dealership replaced the header, the head (as a whole), the oil pump, the list goes on. WHAT THE HELL IS UP, TOYOTA'S DONT HAVE THESE PROBLEMS, MUCH LESS AT 30,000 MILES.

ANYBODY HAD ANY PROBLEMS LIKE OR SIMILAR PLEASE RESPOND...She thinks her ceilica is a peace of shit, I think it is technician error possibly.

the mods include
TRD exhaust, injen CAI, AEM BYPASS VALVE (NO PIPE FROM THE ECM TO THE COOLING FAN DUE TO THE BYPASS VALVE'S SIZE)...thats ALL...

The dealership blamed the problems on the INJEN intake, I know they're full of S!@#$...

When you remove the ecm cooling hose such as she did, does it cause problems...you know the one from the Computer (under the hood) to the botom of the cooling fan, the one you have to cut and modify for the INJEN intake.

Thanks for any help I get, I know toyota means quality, but I need to convince her!!!!!!

thanks

[ 02-11-2003, 03:05 PM: Message edited by: redracer ]

I misfire could be due to dirty spark plugs, or a messed up spark plug wire. If you can connect a scanner to see if it is running lean or rich, that could help narrow the problem.
I don't know why the head and the header were replaced, I can't seem to figure that out, same with the oil pump. Seems to me it could be a technician problem and your dealer is retarded. My 2 cents.

Also, does the code specify which cylinder it is?

[ 02-12-2003, 10:41 AM: Message edited by: SpiderManGT ]