was up guys, i have 92 RS that had a 305tbi now it has a 355tbi with vortec cast iron heads corrosponding manifold mid range cam (1800rpm) not 100% sure on the lift: Im having idle problems, the engine misses at idle and tries to turn off, onece the car is running for awhile it smooths out but when i start to drive it starts all over and i have to dump gas into it to make it stop then the car drives smooth but wont ever go above 2000rpm, and after all that if i have to stop and turn the car off like at the gas station or store it starts up but will stumble and turn off unless i hold my foot on the gas for like 10mins, if anyone can help me out with the cause of this i would really appreaciate it, i put 350 injectors in the car the stock ecm and chip i put a 350 chip in but it made the idle jump all over the place and the car wouldnt even drive, new fuel pump, o2 sensor,map sensor, coolant temp sensor, fan motor,radiator, water pump, and vaccum pressure is good............. please help...........

 

It sounds like you're having a majority of your issues at idle. You mentioned the vehicle was a tbi setup, did you reuse the throttle body from the previous engine or use a different one? Idle air valve was not mentioned as being replaced, maybe getting stuck open partially?

 

im no expert by any means, but i would thing that you wouldnt beable to use anything close to a stock ecm setup to make you motor run properly, its probably needs a new flash( i dont really kno whow much a tbi ecm controlls how it runs tho), i would call a dyno tuner and ask them what they think and if they can tune it for you.....or you could just throw a carb and HEI distributor in it, it willl run just as good as if you left it tbi

 

Head over to the tuning section of the forums.

 

I'm no expert, but I'd also make sure your timing is correct and also make sure your plug wires are in the correct order, then start it up and see if it improves, at least a little. A timing light is a nice investment, regardless of whatever problems you're having. Hopefully, it's not a complicated ecm/wiring issue, but since it's a 355, the 350 ecm probably needs some tweaking.