Stalling 2002, IAC okay, NO MIL or codes?

[stilbo]

2002 Sport Trac...

Stalls when warmed to normal operating temp does not stall when cold.

Weird thing is it will not stall when in reverse!

No MIL No codes.

Stalls when decelerating at stop.. Cruises okay, accelerates okay. Hard restart.

Cleaned IAC valve and replaced IAC hose (was okay but while I was there....)

Checked IAC valve @ 9.4 ohms, not open or shorted. 11.4 volts at wire connector.

MAF wire is clean. No obstructions in air inlet path.

All hoses check okay with no vacuum leaks.

Fuel pump was replaced 6 months before symptoms.

Condition began after owner replaced spark plugs and air filter.

This is driving me nutz.

Can the IAC valve check okay electrically and still not be operating correctly?

Don't want to pop $42.15 = tax to find out it didn't need one.

Thanks,

 

[stilbo]

Bump....

Bit the bullet and spent $82.00 on a new IAC valve.

MOST of the problem is gone but now it will run fine 85% of the time but occasionally it will drop idle rpm to 300-400 rpm while in park... This happens when warm.

Fuel filter new, plug wires check good, coil checks good, MAF sensor clean no CEL or codes.

This guy IS threatening to BUY A CHEVY.

ick....

Thanks

Ron S.

 

[manaen]

you checked your vacuum lines. Did you check the intake gaskets? if this is an SOHC there is a known intake gasket problem. Also when was the last time you replaced your fuel filter, and normal tuneup items?

 

[stilbo]

Owner replaced plugs (Motorcraft platinum plus), wires ohmed good with no voltage leaks, fuel filter replaced three months ago.

I'm ready to agree to a vacuum leak.

Problem is it does it when at operating temperatures and intake manifold leaks on these 4.0's seem to only happen when cold.

Been a long time since I sprayed around an intake to check for leaks and rpm change.

Would ether be better than carb cleaner? WD-40? Don't want to ruin the O2 sensor with silicone and carb cleaner eats plastic.....

Thanks...

8 degrees and I don't want to do anything but sit on my a$$ inside....

 

[manaen]

actually I prefer propane, it is much less messy and has less of a chance of burning your engine into charcoal. Just use a propane torch (DON'T LITE IT of course) and put a hose onto it so you can easily reach the inner parts of the intake.

 

[stilbo]

PROPANE with a hose!

SWEET!

Thanks... I'll give it a try

Ron S.

 

[streetglide007]

2002 ranger 4x4 4.0 sohc starts idles for a moment then stalls. the thing that drives me crazy NO CODES replaced the tps cleaned the maf and replaced the iac did not help . any ideas would help. sorry for the hijack .Ford just updated the cpu now the truck is worse than it was.