Ok a buddy of mine has basically given me a 91 rs t-top 5.0. When i first got it from him he said that the idle would jump up and down a little bit. sometimes to were it would almost die. So i go to start the car and it would not start.. i found and disconnected the alarm and it started. Car ran fine for about a week. So i decide to take it in for a safety inspection and BAM she just shut off while i was driving. The engine just truned off. Now it wont start. The things i have replaced since this process started(per advice on forums)

timing chain,alternator,starter,battery,fuel filter,vacum leak check,all O2 sensors,EGR valve,IGN coil,pick ,up coil,distrubuter,Tps,IACV ,Ignition control,all new wires and plugs

All the fuses are good and the fuel pump does come on. I have not run out of gas. When i go to turn it over she just wont fire. I had a friend look in the TBI to see if i was getting fuel and i am not atm. So now i have to check all the connections and make sure it is not clogged. the only thing i have not changed yet is the ECM and Prom. Could the computer be causing all this trouble? As for the idle issue it had it would normally stop when warmed up but would drop a little low an then catch itself. The computer is not all that much, but i dont want to replace it if it cant be the problem. There are no fluid leaks of anykind either. car and engine are spotless. So my real only question at the moment is weather or not the computer can cause all this. he did mention that he tried to have the codes pulled after the engine light came on and went off but there were no stored codes(I am still waiting to that confirmed myself) Any other things i have not checked yet that could be the problem would be great. sorry for the long post.

 

Are you getting spark?

 

yes she has spark. I have not been able to get it back to my garage yet to check the fuel lines for clogs, I have to go buy a new fuel pressure gage to since my 4 yr old thought it was a baseball bat . I have never had a car just stop running while i was driving before, I dont know but i am going to go out to it today and mess around with what i can. Its in a parking lot at work right now.

 

Well I got her to start today. Didnt do anything but let it sit over the weekend. Now it starts but does not want to stay started. It bogs down real bad so I step on the gas to keep it running. the idle jumps back up, but if i try to give it anymore gas it just wants to die. Sounds like a vac leak but its not. I think my computer may be shot. Fuel lines are good and pump is working fine. Everything electrical has been replaced except the computer.

 

i had a similar problem. went through the starter, battery and check the fuel pump/filter situation. swapped out my computer and it didn't make a difference. the car still has a little bit of a problem with it and i don't know what it is as it's been to 3 different mechanics. if you figure it out let me know too.

 

If you are getting fuel and spark, the only thing left is air. I am assuming you did a full tune up, the long list of parts you provided would suggest that, how is the timing? Is there a strong odor of fuel or the smell of a lean mixture? I am not 100% sure about TBI's but I would think they could get out of whack and might need to be adjusted. Also what work was donr to the motor before you got it, like is there an after market cam installed?

 

I'm not too familiar with TBIs myself, yet. I'm used to carbs or EFI, not this bastardized mix of the two. lol

Could the computer be retarding the spark if it has a bad sensor or a bad signal? The TPS or the O2 sensors would be my guess, but you said you replaced those, so I don't know. Sounds to me like it's getting mixed signals from somewhere and doesn't know how to cope with it, so it goes haywire. Do you have a big stereo with unshielded power cables? Just a thought. Ummm . . .are your plugs gapped correctly? Sounds to me like a timing/ spark issue.

 

Check the Throttle Positioning Solenoid, mine took a dump, but before it did the idle was erractic, i was sitting at a traffic light, and the car revved up and wanted to lunge forward! had i not had my asphalt boots on, to much brake pressure! LOL anyway she did finally quit but get the aftermarket one that is adjustable, probably is not the problem but you replaced just about everything but that? and ecm. But look at it this way when she does run and run it will, you will have one hellava nice restored maro. Good Luck.

 

I would still drop the tank and check the fuel pump it still might be bad. Sometimes it takes awhile for it to completely stop working or try putting more gas in it because when mine was replaced I don't know what they did but I am empty with a a 1/4 tank of gas, or your strained might be clogged.

 

What about the relay wirering for the Fuel pump(fuel pump to the Fuse box). i have a 86 irocz and the SAME thing happend.. First time it was there was a loose Connection(a short that burned the fuse.. ) so i had a mechanic take a look and he fixxed it.. then a week later i was driving then it just shut off.. Angry i was for spending $$ to get it running i brought it to GM and well.. My igition coil was the problem.. Car has been running like a champ ever since.