Ok, my 91 Full size will start but will not idle, even when you give it some gas to try and keep it running it will rev up but if you try level it out it will die. I have changed plugs ,wires, cap, rotor, Air idle sensor, and TPS??? Any ideas out there???

Thanks for your time!!!!!

 

91 K5 350

Symptoms:

starts and runs for 3 sec.
good fuel flow for 2 sec.
good spark

Fuel relay replaced
In line fuel filter replaced
Air idle sensor replaced
TPS replaced
Rebuilt Fuel Pressure regulator, and TB


STUMPED!!!!

 

Any vacuum leaks? EGR clean and operational?

BTW, I merged your two threads. Please try to keep to one topic on a given problem. You can always bump the post if you have not received a reply after waiting 24 hours or more.

 

Is the Idle Air Sensor the same thing as the Idle Air Control (IAC) that is mounted on TBI? If not I would check that. I would check the voltage of your Throttle Position Sensor at idle (It may be out of spec. a scan tool can read the voltage). How are your injectors? EGR if leaking can cause idlw problems as at idle the EGR should be closed.

 

Thank you all for your response's, I need some more please...EGR is good, TPS has the voltage, The Idle Air Control Module in the TBI is what I replaced.

There are some people telling me that it is the fuel pump, I guess I will buy a fuel pressure guage and let you all know if that is it....

Thanks again for all the ideas!!!!!

I do apologize for the two post swartlkk but it seemed the other post was not getting any responses????

JDO

 

I have dropped the fuel tank and it seemed as if the hose on the fuel pump was real gummy (nasty feeling) so I just ordered and new sending unit and pump...Will let you know if that was the problem....I hope...I hope.....I hope