Hello everyone, I'm new here and I was hoping I could get some help. I have a 91 f150, 5.0, 5 speed, xlt lariat. It has 46,000 miles on it and all original. Truck has, flow tech long tube headers, true dual exhaust with Flowmaster 40's, and a jet performance fuel management system. Before all of this was installed, when it's colder out and it's the first start of the day, I have to feather the throttle to keep it running. I only have to do it for a minute or so then it's fine. I had a problem with the IAC a while back. Cleaned it, and she was fine. Again, this was happening before I put all the goodies to her. Bone stock it was doing it. Just wondering if anyone else has had this problem before? Thanks in advanced,
Chris.

 

Check for codes.....

Verify fuel pressure....

Take off the "jet performance fuel management system" what the devil is it?

 

Only codes are for the egr that was deleted. Haven't done a fuel pressure test, but it's only when it's cold. If the weather is warm, it won't do it. The jet performance is a chip that re-maps the speed density system. Again, the problem was happening before everything was put on.

 

No codes, verifying fuel psi is a great idea.


Next step, get a Haynes manual, start checking sensors.

 

I have checked, cleaned, or replacedo every sensor I could get my hands on. The only thing I can think of is my iac is not working correctly. Any thoughts?

 

Since you shotgunned the problem before...the only thing left is the IAC.