IMRCs - no idle when engine cold

[husky017]

I have a 96 Mark with 110,000 miles...last summer the car began idling rough at startup and the problem became progressively worse. Up to the point of storage last fall, it would take at least 2-3 starts to keep the motor running, like it was starving for gas (whether it is or not). After warming up it runs fine.

Ever since the problem began it threw a CEL with 'IMRC stuck open' code. I'm planning on replacing the actuators soon here, but does this problem sound like a direct result of the IMRC's or could it be from something else not throwing a code?? Thanks..

 

[NoLimit95]

Replace the throttle position sensor (TPS), I just done mine last week and now I'm back a normal idle at start up. I had the same problem as you. When I would crank it up, I would have to stay with it for a few minutes until it warmed up enough to idle on it's own and the idle would be smooth but very low. Even after it warmed up during driving, it kept a very low idle at around 500 rpm but now that I have changed the TPS, it will crank up without touching the gas and I now have an idle of around 700.

Average $30 part and not one of the easiest to change but it could be worse. Get a new throttle body gasket too. Both parts cost me about $38 not including the TB cleaner. Also spray the bore out that's just to the left of the intake that goes to your IAC valve. I think this will help you out a lot. Jamie recommended this fix for me and he hit it on the money.

 

[Markviiiedrea]

Replace the throttle position sensor (TPS), I just done mine last week and now I'm back a normal idle at start up. I had the same problem as you. When I would crank it up, I would have to stay with it for a few minutes until it warmed up enough to idle on it's own and the idle would be smooth but very low. Even after it warmed up during driving, it kept a very low idle at around 500 rpm but now that I have changed the TPS, it will crank up without touching the gas and I now have an idle of around 700.

Average $30 part and not one of the easiest to change but it could be worse. Get a new throttle body gasket too. Both parts cost me about $38 not including the TB cleaner. Also spray the bore out that's just to the left of the intake that goes to your IAC valve. I think this will help you out a lot. Jamie recommended this fix for me and he hit it on the money.

I had the same prob

I had to do mine four time's I kept trying used parts (free ones from a u-pull-it yard) I just baught a new one for 41 bucks I think.

It's easy to do just get the throttle body off and its on the back side. i had it down to 20 min.

 

[unity]

The IMRCs should not cause a stall out. While there may be a problem with them, its not the cause.

While it could be the throttle position sensor, I am leaning towards the classic IAC (Idle Air Control) valve problem. I say this because you mention that its a problem when cold. The IAC, if bad, is worse when cold.

Replacement is the same as the TPS. Its right near the throttle body.

You *could* put on a new TPS and IAC since bother are not easy to get too. But then you are sorta throwing parts at it... $$

 

[husky017]

yea kinda thought the IMRCs wouldn't cause a stall..which is why i asked. think im going to go ahead and replace IAC valve and TPS and give the TB a good cleaning...thanks for the advice

 

[unity]

Careful what you clean it with. Make sure its Throttle Body cleaner and not Carburetor Cleaner. Apparently there is a film on the body that does something critical. Some have cleaned it wrong with bad results, others cleaned the same way and everything seemed fine. No clue what it is on there, but you have been warned!! LOL

 

[husky017]

yea they make TB cleaner for a reason..that carb cleaner is strong stuff

 

[NoLimit95]

If you have never done this before, the first thing you need to do is remove the pass side wiper so that the plastic piece can be removed. If not, you will be getting to it before that TB comes out and the plug only comes up so far for the TPS so be careful when unplugging it.

Another thing to be careful with is on the drivers side of the TB, you will have a rubber (T) connected to the TB and two other hoses. Be easy with that piece because you will not find another one at the parts stores unless you order it from Ford and it's most likely discontinued.

I covered the entire top of my engine with a towel and sprayed the under side of the TB with STP throttle body cleaner. I let that set for about 20 min and then sprayed again and more build up come out. After about 6 good sprayings, it was nice and clean again. Going from a 400 to 500 rpm idle up to a 600 to 700 rpm idle made all the difference in the world. When stopped at a light, I don't even feel the car running anymore. I never touched my IAC, I only cleaned out the bore hole to the left of the intake hole using the TB cleaner. I had very little carbon build up in there.

Once you see how hard it is to get to the IAC, you might also change your mind. I just took the chance and left mine alone and it's running like new. I'm not saying not to change it but I just didn't want to tackle that part of it. I got lucky and it runs fine after the TPS change. There are two different styles for your car so make sure to match yours up with what they have where ever you get it. I got mine from AZ for $28.99 and the gasket for $7.99 + tax

Ford parts wanted $67.00 for the TPS and $17.99 for the gasket + shipping and taxes. The sensor I got from AZ used to have FORD marked on it but it was smoothed out. Picture of mine are below. The new one is on the right side.

 

[Roadboss]

Most of the problems are a result of the IAC Valve sensor. The TPS seldom goes out by comparison. BTW NAPA has the better quality unit in the aftermarket, it also carries the FOMOCO #