I have a 1989 half ton custom.300 I6 4 spd w OD no air 2wd with 219000 miles.
The truck runs great when the outside air temp is below 40 degrees, but as the weather has been warming up, it is getting an idle problem, and depending on the outside air temp the problem gets worse the hotter it gets. It seems like something is telling it it needs more gas at idle than it actually does. Sometimes it will just die unexpectedly, and won't start again until it "decides to."
I have replaced both fuel pumps, (rail and tank) a coolant sensor, the TPS,the map sensor, the egr valve and sensor, and now am thinking about getting an O2 sensor,
When going down the road it doesn't miss a lick, it starts acting up at idle.or at lower rpms. This past winter when the weather was at 20 degrees or below, it ran like a new one. Anybody got any ideas ???

 

TFI modules & PIP sensors both become temp sensitive when they are reaching the end their useable life spans. I believe your TFI in mounted on your distributor. The PIP (or Stator) is located whithin the distributor. Distributor removal is required. PIP's are $12-25 by themselves. Many replace the distributor as a unit to save time & hassle.

In cases where the TFI is distributor mounted, it is strongly recommended both the TFI & PIP be replaced at the same time. TFI will not come w/ a replacement distributor. Cordone Distributors have a high "out of the box" failure rate.

PIP: http://www.fordfuelinjection.com/?p=25

I would run error scans first: https://www.f150forum.com/f10/how-re...es-obdi-10907/

Or buy one of these to do scans: http://www.handsontools.com/Equus-In...ol_p_5574.html

 

I don't see the IAC on that list.

Unrelated, but they stopped using the 4 speed OD in '87. I'm guessing you mean the 5 speed.

 

I was waiting for you...oh, you mean 'his" list?

 

Either or.

 

Understatement of this century lol.

 

sorry, I guess I should have said 4 spd with od

 

Thanks for the replies. Forgot to mention I had the ignition module replaced too at a local garage would this replacement include the pip and the TFI. this evening, it died on me on the way home from work while going downhill, and could smell raw gas. When I finally got it started. I had to rev it to 4000 rpm before it ran smoothly, but when going down the next hill, it "acted up again." I really appreciate the ideas and feedback.

 

Well now you're sounding a little like a pooched fuel pressure regulator. You would need to take pressure readings at the fuel rail to know for sure.

See link: http://www.fordfuelinjection.com/?p=41

No, a new TFI doesn't guarantee the PIP got replaced, Although it is strongly recommended to do so at the same time, as their lifespans are nearly identical.

This is because they share the same power circuit as well as ground. Otherwise, you find yourself in the same predicament again, as the symptom for failure are almost identical for both components.

Read the link I posted regarding the PIP!!!

 

No, that's a 5 speed. There's a 4 speed with underdrive and a 4 speed with overdrive, both only having 4 gears.