i bought an 88 iroc, been sitting for 6 years. so i pulled the tank and cleaned it and put a new pump in as well. i also put a new engine in it, nothing major 355 with LT4 hotcam and headwork. got everything in and hooked up. tired starting it and it acts like is out of time and running on 3 cylinders. it has ran before, pretty good actually for a few minutes and then went back to running like crap. the timing is set at 10* advanced. the car doesnt even want to start, if it does it runs like crap and you can give it as much gas as you want and it doesnt budge. ive replaced the ignition module, put a coil on it and still nothing. it seems to start and run better with the MAF unplugged but it doesnt last long. im getting frustrated with it and dont know what else to do. im thinking about replacing the ecm but i dont like to just put parts on and hope it fixes it. id appreciate any advice or help from anyone. thanks

 

You cleaned out the tank but did you clean out the lines and put a new fuel filter inline?
and when you cleaned out the tank was it just bad fuel or was the crap/rust in the tank?

 

i cleaned the tank, wasnt any rust in it, cleaned the lines, has new pickup and pump. it shows about 45 psi fuel on the gauge, when it does run. i put an ecm on it and had no luck. im gonna re-check the valves and make sure they're not to tight

 

did you replace your injectors? when i bought mine it was doing the same thing and it had two bad injectors. if and when you get the car started back up try to unplug the injectors one at a time. it will make a difference in the way the car runs. the funny thing about mine was i unpluged the bad injector/s the car ran better almost perfect. my injectors were stuck open and back feeding to the ECM.

just a thought