well, this is my cousin's car actually, we went out to the sac raceway last nite and he was running fine but durin his last run, he said his car bogged down on him. he miss-shifted into 3rd gear and i think he hit the limiter on his 90 teg gs. anyways, he came back into the pit area and his check engine light was on. the ecu was throwing a code 4 and a code 9. what are they? the car seems to not have enough gas, i mean it idles fine but if you step on the gas (even parked in neutral) the car seems like its out of gas and its about to die. he says once he drives past 2000 rpm, the car is ok, but he can't go past 3000 rpm otherwise his car will bog too...what could this be?

 

bent valves. Time for a leak down test