'99 Windstar, 3.0L engine (I think) with 205,000 miles.

When starting the van cold, the engine stalls when going from Park to Drive or Park to Reverse. If I let the van idle for 10 minutes plus, then it doesn't stall. When the van engine is warm, after driving around for a bit (or a long time), the van never stalls when shifting out of park.

I am thinking it may be a vacuum issue. Engine light diagnostic (at AutoZone) indicates a vacuum leak (non-specific). My theory (that needs to be affirmed or challenged by the reader) is that the vacuum leak is at the intake manifold/engine gaskets. If I replace the gaskets, (me thinks) this will solve the problem. I say this because after the engine is warmed up, I have no problem. So I think that, with heat, the engine metal expands, closing up the leaks that may be through the "leaky gaskets".

Maybe the problem is not a vacuum leak at all???

What say you?

Thanks for your thoughts, ideas, advices and solutions.

Weekend Wrench

 

After reading Digital_Diversions "'98 Ford Explorer..." post, I got to thinking about the IAC. Would a stuck IAC cause the symptons that I describe?

I think changing/cleaning the IAC would be a whole lot better than changing the upper and lower intake manifold gaskets.

Thanks for your thoughts,

Weekend Wrench

 

yes it would and it shows up in cold weather the most on first start up .thats where to start is that IAC.

 

check out the intake gaskets for leak....rule that out first...

start when cold.....spray a bunch of carb cleaner around intake gasket areas and see if it sucks in carb cleaner and kills engine.....

check iac mechanical operation to rule it out....its easy

take iac off intake...leave wire harness plugged in...and have someone turn ignition off and on a few time and watch for bypass valve movement inside IAC.......

what code was it exactly???

 

Thanks guys for your ideas. Sounds like I'm on the right track. It's 8 degrees in Chicago and my wife hasn't bought me a garage heater, so I need to wait awhile. But I will get at this soon. I think my Haynes book provides info on the IAC location, so I'll get at that soon, and also spray carb cleaner into the intake.

Quick clarification, when I spray the carb cleaner and it sucks in and kills the engine, does that mean that there is a vacuum leak and I should replace the gaskets?

Also, in checking the IAC mechanics by turning the ignition on and off, do I just turn the key on and off or do I start and stop the engine? If the IAC is sticking, I'll try cleaning it first, then replace if required (quote of $179 at the Ford dealer).

Thanks for the additional details Mr. _Diversion.

Weekend Wrench

 

the carb cleaner trick is that if there is a vacuum leak...spraying it around the suspected leak means the leak will suck in the carb cleaner and thus kill the motor...since engines dont run well on carb cleaner....

when testing IAC...you don't need to start the motor...just turning ignition on and off will activate the IAC piston....it wont move much...just enough to close the bypass.....if no movement...then clean it and lube it (search my posts for info on how)

 

you are trying to find the leak...if you spray carb cleaner at a point where there is a gasket leak and it sucks the carb cleaner in and kills the motor....you have found your leak...and you need to address it...replace gaskets...replace cracked hose...etc


double check hoses for cracks and such....pcv valve hose also....

 

just make sure the air cleaner isnt sucking in carb cleaner fumes....defeats your purpose....


just making sure you understand you are not spraying cleaner INTO your intake....but around the motor area where you suspect a vacuum leak....if there is an intake manifold gasket leak..it will suck in air (or carb cleaner)...the same will happen if you have vacuum leak somewhere else....

 

Mr. _Diversion,

Great details. Will do soon and will report back.

Thanks, Weekend Wrench

 

PLEASE Help!! I recently bought a 2000 ford windstar and it cranks and runs great until it warms up then starts to sputter, buck and stall especially when at idle. I have replaced the crank position sensor and its wiring, replaced the mass air flow sensor. and the idle air control valve, and plugs and plug wires. I cant find any vacuum leaks and the fuel pressure is fine. WHAT SHOULD I DO!?????