Bad Idle and Stalling

[flosho]

Well I FINALLY bought another SHO! After a month without one. Anyways... This new SHO of mine does have a few problems...

1.) Car has a rough Idle. It doesn't really have a specific time when this problem occurs, I mean it doesn't matter if the AC is on or if the engine is warm or cold. If I come to a stop at a light the car sometimes drops the idle below 500rpm and then up to 1000rpm then back down... Then it'll ****.

I checked the plug wells for oil, I didnt really see oil in there. I read up on and I'm thinking I have to "re-learn" the idle..or clean the IAB/IAC. Do these solutions sound correct??

2.) The car seems to miss once in a while. I can be going 30 mph and it will kind of chug... but not REAL noticable. Then I kinda took it for a test run. It seemed to pull real well through 1st but it kinda stalled at 60 the RPM's remained constant(but I had it at WOT) then it would kick back in(almost like a THIRDarie) wink

To fix this I checked the front plug wires and I think this missing problem could be caused by one of the plug wires. At the end of the wire, where it connects to the plug, there is a rubberish peice that fell off/is loose. So maybe this is affecting the connection.


Its a 93 ATX with 85K... What is your guys' imput on these problems?

Any and all help is appreciated

 

[OSHSHO]

My '93ATX had identical problems. The stalling and bad idle is more than likely from clogged "nostrils" in the intake manifold. Mine were not even visible, I had to feel for them!

I removed the intake, cleaned it real well(3cans of Berrymans B-12)without taking it apart. I installed new Motorcraft Plugs, Valve cover gaskets, Taylor 8mm Spiro pro wires, and now it runs like a champ.

 

[flosho]

How long of a job is it to take the intake apart, clean it, change the gaskets? Can the gaskets be bought anywhere? Or do I have to order them through FORD? Monday I got some time so I'll probably take the intake off and clean it at least.. and put my Bosch Platinum 2's in.

 

[sdpatt]

You can clean the intake without taking it apart. There is more damage to be done by disassembling it than to be gained by the more detailed cleaning. Use a nylon bristle brush on the runners.

The main thing you need to clean out or check is the idle air control valve (IAC) which can be removed without removing the intake. If this device is sporadically malfunctioning, it could cause the symptoms you are describing, but then the spark leak and misfire you describe can also cause it. The IAC valve will not cause the flat spots off idle you describe. Fix the plug wire(s) first, then worry about the IAC valve.

 

[Markus]

sdpatt:
You can clean the intake without taking it apart. There is more damage to be done by disassembling it than to be gained by the more detailed cleaning. Use a nylon bristle brush on the runners.

The main thing you need to clean out or check is the idle air control valve (IAC) which can be removed without removing the intake. If this device is sporadically malfunctioning, it could cause the symptoms you are describing, but then the spark leak and misfire you describe can also cause it. The IAC valve will not cause the flat spots off idle you describe. Fix the plug wire(s) first, then worry about the IAC valve.

Scott, you've got my mind working overtime now. With the exception of the gaskets, what is there to damage by taking the intake apart? I've just had mine apart for the second time. The first time I was able to reuse all gaskets (except IAC valve gaskets). This last time I purchased new gaskets even before I started. I must be missing something!


To all those who remove the IAC valve - be very careful with the gasket. It is a reusable gasket but it must be treated with care. You can no longer purchase it from dealers.


There are some IAC valves that are not be be cleaned. These have an anti-sludge coating inside them and throttle body cleaners will remove it. If you don't know which IAC you have, and it is funtioning properly, then you probably shouldn't clean it. The IAC valve on my 1995 ATX is a non cleanable type. I don't know about other year SHOs.

<small>[ April 19, 2003, 05:33 PM: Message edited by: Markus ]</small>

 

[Markus]

flosho:
How long of a job is it to take the intake apart, clean it, change the gaskets? Can the gaskets be bought anywhere? Or do I have to order them through FORD? Monday I got some time so I'll probably take the intake off and clean it at least.. and put my Bosch Platinum 2's in.

I took 4-5 hours to dismantle, clean, and put back together my intake components. There are those who will say you can get it clean enough without dismantling it. This may be so, but if I am cleaning something I like to get it as clean as I can. This means dismantling.

I replaced all gaskets except for the IAC gaskets with are no longer available from the dealer. Note that this is the second time I have cleaned the intake, and the first time (3 years ago) I reused all gaskets.

If replacing the gaskets you need:

E9DZ-9H486-B (package of 4 butterfly-to-plenum gaskets)

E9DZ-9H486A-A (package of 2 runners-to-plenum gaskets)

E9DZ-9439-A (package of 2 intake-to-head gaskets)

Throttle body gasket

EGR valve gasket.


Note that included in the 4-5 hours was a thorough cleaning of the throttle body. My throttle body has a label on it that says "DO NOT CLEAN INSIDE THROTTLE BODY". This is because there is an anti-sludge coating that throttle body cleaners will remove. I used diluted dish washing detergent.

You might want to do a forum search for the Bosch spark plugs. Some people have not had good luck with them.

<small>[ April 19, 2003, 05:27 PM: Message edited by: Markus ]</small>

 

[flosho]

Where exactly is the IAC? How do I go about cleaning it??

TIA