just got my first vette , it starts up and idles fine but after driving it a while starts missing wont take gas dosent die restart runs a little better what could cause this

 

I would check fuel pressure, and replace the fuel filter. If the pressure is low after changing the filter then the pump is dying. If you are lucky it may just be the filter. Post what you find so we can take it one more step.

 

See link below, this is what you need asap.

http://www.ebay.com.au/itm/1985-Chev...item4853517f76

You can start by checking the throttle position sensor voltage, should be 0.54 volts d/c at idle or ignition on (measure top and middle wire)
Also check it goes to 4.5 volts d/c with full throttle.

If that still does not help you may need to reset the base idle, the ecm needs this to be done correctly to manage easy engine starts hot or cold.

Set your car to a base idle (as per my shop manual)
when hot.

Connect a paper clip, to your diagnostic terminal under your dash connect to terminal A and B (the top right two pins).
Turn on ignition but don't run the engine.
wait at least 30 seconds and then remove the idle air valve connector (IAC) (the square plug) then turn of ignition and unplug the paperclip.
Now remove the timing connector a single wire near the fuel pump relay.
Start your vette and set the idle speed to 400 rpm in neutral (auto trans) 450 rpm (manual trans) then check your throttle position sensor,
the top two wires it should be set to 0.54volts dc, also confirm with engine off that the tps rises to 4.5 volts at full throttle.
Turn of the ignition and reconnect the iac valve connector and timing connecter and start your vette.
it should go to 1200 rpm then drop slowly to 600 rpm, take the car for a 15 minute drive with the usual stop lights.
It is normal for a little hunting while the ecm relearns, also do a few spirited take offs.
All should settle after 15 to 30 mins normal driving and have a stable idle.
Of course any vacuum leaks fouled plugs can affect the correct base idle.

Good luck

 

im leaning toward fuel pump assembally if cut hard it acts up i pulled out this morning not even warmed up yet turned a sharp turn it started doing it , thanks im sure i will have more questions

 

not fuel pressure and i forgot to mention check engine light comes on

 

How full is your gas tank?? Sharp turns and the car misses could be fuel starvation, these cars should not run less then 1/2 tank of gas ...I don't know if this would cause the light to come on......WW

 

i finally got a chance to play with my car here is the symptoms , put a fuel pressure gauge on it taped it to the windshield , starts and runs fine drive down the road and starts cutting out fuel pressure never dropped , just turn the key off restart runs fine now i got to save my pennies gonna try a egr can the burn off relay do this or mass air flow do this it like something opens up or closes and the problem starts , any help is appreciated

 

Have you pulled the fault codes? The SES light is talking to you but you are not listening.

 

i will in the morning

 

Your catalytic converter might be restricted (getting clogged up) and you have exhaust gas pressure building up after it runs a bit.

 

but would it run fine after i restart ? it messes up just restart run fine then starts again

 

If the converter were restricted, then after you shut if off the first time and re-start, it will run fine at least for a short while because the exhaust pressure will bleed off. But the condition should re-occur. If you're saying that after you restart, it will run fine for as long as you want to drive it, then that's truly an odd problem.

 

A lot of problems can be found by hooking the car to a scanner. Maf, tps setting, timing , any bad sensors , these and more will all show up with a scanner....Hooking to a scanner is always my first suggestion when troubleshooting these cars......WW

 

What's the mileage and the maintenance? Run's bad in closed loop. Could be a dirty MAF to .....Name it.
Get the trouble engine code and start looking for the obvious.

And the fun begins.

Good luck.

 

my car has a 126,000 not maintained well but i did pull code 12 this morning

 

Code 12 is a delimiter or marker code to show where the error code string begins and ends. Everyones car has a code 12, all the time...WW

 

yea the ecm says there is nothing wrong checked fuel prressure it didnt drop while i was driving it ran about 35 37 but it did bleed off within a a few minutes
after i shut the car off

 

no its reoccuring event and getting worse

 

If the check engine light is coming on, then there is some other code besides a 12. I'd go through that procedure again first. If I recall, the 12 will flash 3 times, then it will go on to other codes.

If your fuel pressure is good while you're driving, my money is on the catalytic converter being clogged. It would be a little loud, but you can remove it and test drive it to see if that's the problem without spending any money.

 

I just recalled someone else complaining of a similar problem a couple years ago and said it was resolved when he replaced the HEI ignition module.