I have an 89 f150 super cab... 300 il... efi... on startup it idles fine for 10 seconds then idles ruff and stalls out till it warms up... just started doing this recently...

 

How old are the spark plugs, wire, cap and rotor?

How old are the air and fuel filters?

Have you checked for codes?

Welcome the FTE!

 

Plugs, wires, cap, rotor, fuel filter... replaced last year... air filter is fine... it's an OBD1... hard to find a garage with a scanner...

 

You can check your own codes. Follow the link: Ford OBD Trouble Codes ?

 

When it idles rough does the RPM fluctuate between normal and lower? You said it 'stalls out' does that mean its dying and you have to restart or engine misfire and its stumbling? I'm not an expert but thought a little clarification might help the forum members that are. Welcome to FTE, lot's of good folks on here.

 

Yes... the rpm's fluctuate and it stalls out after a few seconds... i have to restart it...

 

Looks more like a sticking IAC (Idle Air Control) solenoid. A rolling idle can also be caused by a faulty TPS (Throttle Position Sensor) or vacuum leak(s). Could be a combination of all of the above. Process of elimination.

The IAC can be taken apart and cleaned, but many times this is only a short term fix. For reference: IAC/IAB

 

I had the same problem on my '96 F250 7.5L EFI. My IAC was so stuck 2 cans of carb cleaner couldn't free it! rla2005 is right on the money. IAC valve $44.95 at Autozone and 10 min. to swap out.

 

Thanks for the vote of confidence