I have a 1994 Ford F150 with 5.8. It idles perfect when not moving but whenever I accelerate and let off to come to a stop, it idles low and cuts off. Anyone have any idea what might cause this? Thanks.

 

need more info. what trans? pull codes?

 

E4OD. No codes or CEL. Vacuum 21 at idle.

 

Have you checked the iac to see if it's sticking?

 

No I have not. Be a good place to start.

 

Cleaned IAC and checked resistance/voltage and problem is still occurring. Also checked transmission filter to see if it fell out and it had not, but I replaced it anyway along with fresh fluid.

Didn't mention I did an EGR delete because I didn't think that would have anything to do with it but it could for all I know. I vacuum capped everything, plugged the heads, and soldered resistors to all of the different solenoids. No codes or CELs.

Like I said before, even after the EGR delete, vacuum is steady at 21, idle is steady around 900. Maybe next place to check is TPS???

 

Even though you cleaned the IAC it can still be the cause of your issue. But before throwing parts at it verify the TPS output is within specification at closed throttle and increases smoothly when opening to WOT. Watch for any dips or spikes.

 

TPS checks out perfect. Worst part of all of this is that it only happens occasionally...