I have a 93 940 SW Sometimes at idle the engine will stumble and the exhaust will get a deep throaty rumble. I rev it up and bot symptoms go away and then at random times it will do the same thing. No "check engine" light on. I sure appreciate your help and I appreciate this forum. Thanks in advance.

 

The first thing I would do is clean the throttle body and idle motor.

The idle motor being dirty can cause that.

 

Thanks for the response, Tech. Can you talk me through it. Do I take the black hose off that leads to the breather? And where is the idle motor? Also can i use carb cleaner to clean in there?

 

It would be best to remove the throttle body all the way.Follow the hose from the Air filter box to the engine.The hose connects to the throttle body.Remove the little rod.Look at the rod one side on the end of it unclips.Then the rod will slide off.Then unplug the throttle position sensor on the side of the throttle body.Then remove the 3 nuts and the throttle body will slide off.

Use Carb. cleaner to clean it out.Then reinstall with a new gasket.

The idle motor is under the throttle body mounted to a bracket.It looks like a cylinder with 2 hoses going to it.

 

Thanks Tech, I live in a small town and I can't find a gasket for the throttle body. Will I do reasonbly well to clean it on the engine?
I like so many on here surely thank you for all your help!!

 

If you clean it on the car let it sit for a while before starting it up.

That will let the excess to evaperate.

 

Tech, I sure appreciate your help. On the idle motor, what do I clean in there? Is it just a hollow cylinder? Also is there anything in there that carb cleaner will hurt. Thanks again.

 

Nothing to hurt.Spray in there and let soak for a couple the make sure all is out.
I always use a pick and work the motor to make sure it isn't seized.if you look with a flashlight you should be able to see how it works.Then I spray a touch of WD-40 or something like that in there to help keep it lubbed.

 

Tech, I sure appreciate your help. I cleaned both the throttle body and idle motor and both were kinda dirty, Now my complaint is that at idle with AC on and in gear the engine will surge about 200 RPMs. It happens mostly when the engine is at full operationg temp. Any ideas???

 

Is the compressor noisey at all?

 

Thanks Tech, No the compressor seems quiet.

 

I wonder if the clutch bearing is getting old and tight.

That is the only other thing I can think of.

 

Tech, do you think it could be his/her Throttle Position Sensor? I've seen the TPS send random currencies of voltage when they go bad, causing surging and severe drops in idle. Just a thought.

 

That is very well possible as well.

 

VN Mustang. I had a 93, which I sold, had the cop package+an S-Trim blower I put on. Then I bought a 96 Mystic Cobra, which I went WAAAYYY overboard on. Sean Hyland Motorsports and Mustang Parts Specialties made a killing on me. LOL. Nice to meet you Tech.

 

Nice to meet you to. I wish I had the money to make mine half of that!!! LOL

 

Ahh, more Mustang guys.

My '88 LX 5.0 has been wonderful (owned from new) but it's time for me to sell. I'm gonna miss that car!

 

They are AWESOME. Cant wait till I get back to normal with money to start buying PARTS!!!!!!!!!



I need more Power!!!!


If you are ready to sell goto this site and post it for sale. It is a sister site of this one

http://mustangforums.com/

 

I'm still having surging troubles but I have narrowed it down somewhat. When I put it in park, or come to a stop or the AC compressor cuts off seems the engine idle will surge up about to about 1000 RPM's and it seems like some sensor is trying to adjust it back down to 750 RPM's but it over reacts and drops to about 450 RPM's and back and forth. I DO NOT have a check engine light on. I have cleaned the throttle body and idle air motor off the engine. All the ignition is new, {plugs, wires, cap and rotor} I, again appreciate this forum. Thanks Tom

 

Your compressor might be working to hard and thats why the idle is low with the A/C on.

Do you have any problems with idle with the A/C off?