99 Silhouette 3.4L Premiere edition stalls/wheezes/whistles

[99silhouette]

Hoping someone here has an idea as to what I might check.

When starting and left idling, the van runs fine. Once I begin driving the van will start to act up within the first 3-5 minutes. It acts as though it is choking, rough idle, 100-1500 rpm, back and forth, then dies. It seems that if I can manage to get the engine nice and warm, the choking subsides at a constant speed. So, highway driving is fine once I'm going, city driving is a bit more challenging and results in multiple stalls and restarts.

One more piece of the puzzle may be a noise I heard for a week or so before I started having the stalling problems. After a good long drive, I'd shut the engine down and I'd hear a wheezing/whistling sound for a few seconds. I suspected vacuum line of some sort, but I could never pinpoint the location because it would subside before I could get the hood opened to take a good look. Maybe someone has an idea there.

Ideas?

Some background may be in order first. In the past 12 months a number of issues have arisen which have cost me close to $5k. Most electrically related. My mechanic found a short in the system, but now I'm wondering if that was the only one.

New battery (2k miles)
New fuel pump / filter (5k miles)
New ABS/TCS control module (1k miles)
Driver Front ABS hub sensor blown (1k miles)
New Drivers Rear turn signal board (10k miles) corrosion
Overhead Console DIC died, circuit board for the LED output is burnt internally (12k miles ago)
Video Entertainment system (monitor) has stopped working (6k miles ago)


New upper engine gasket set (5k miles)
New belt (5k miles)
New hoses (5k miles)
Transmission Flush
Engine Flush

[diesel1962]

Hi. I think these vans have a vacume cannester under the hood.I would check it for cracks.Also check all vacume lines and the plastic nipples that the hoses plug into.Also the A/C system will make a small hissing sound when the engine is shut down.Let us know what you find out.Diesel 1962..(Former Old's Silhouette owner)

[merc81]

How many miles on that beast? You mentioned upper engine gaskets, I'm assuming you meant intake gaskets. Does it miss a little when first started cold? Have you noticed any sludge in the coolant overflow bottle?
I'm getting at maybe a leaking head gasket--sounds like it might be about time from all the other items you mentioned. I'm doing my head gaskets right now and the way it acted just prior to total failure of the gasket sounds about like what you described.
Don't take that to the bank, just musing outloud. Tell us some more details about the age and condition of the engine, check engine light status, etc.

[99silhouette]

Well, turns out the crankcase sensor wiring harness had come to lay across (or very close) to the exhaust manifold. The wiring protective cover was gone, just bare wire. When accelerating, turning, etc... the wires would arc.

Now I'm wondering if the work done on intake manifold gaskets and valve cover gasket replacement led to the wiring harness being layed across the exhaust.

My electrical problems (ABS module, video monitor, Driver Info Center) all started about a month after that repair. Hmmmm....

By the way, the van has 130k, after replacing the first intake manifold gasket set (out of warranty) at 28k miles, I would have said it never would see 130k+

[diesel1962]

It sounds like you found your problem!! Merry Xmas !! Diesel 1962