Engine idle problem '94 SC

bubble-city

Registered User
Hello,
I am a recent SC owner, and I must say, the car is a lot of fun to drive. I do have a problem with it, though. I searched the tech forum, and found similiar problems, but not exactly the same. Hopefully, someone can help. The car runs great, but will die every once in a while at idle. It is a very intermittent problem. Sometimes it will die two or three times in a 15 minute drive, then not again for a week or two. Or it may die only once, and then again later in the same day. Sometimes, it will "shudder" at idle and not die, other times it will just die without warning. The engine may be cold or at operating temp, no real pattern to it. The car always starts right back up, and runs great. This is very frustrating at times. I've checked for vacuum leaks, and am at a loss as to what to check next. I had a tempo years ago that acted similiar, but didn't own it long enough to care. Anybody have the same problem, or know where to start?
Thanks, Mike.
 
Dose the check engine light come on and go out on restart? If so my 94 did this and it was the cam sensor. Next I would check for codes. It could be the IAC also. These cars are very complex as far as trouble shooting sensors. My first 94 runs diffent every time I drive it. Most times she cant hook up till 40 or so and every now and then your lucky to chirp second. I dont know, I have changed almost every sensor with no codes but I will keep digging.
 
It's a Super Coupe. You'll learn to live with it.:D

Seriously, though. Sounds like a sensor. Good time to invest in a Code Scanner.
 
Bubble I have the same exact problem on this side. If you figure it out could you let me know, and if I do I'll let you know now.


How much does a scanner cost?
 
I could only suggest running some fuel injector cleaner through. I have similair problems when the car is cold, but only since I put everything back together. My car has trouble keeping idle when cold, then again, a stock ecu with all i've done, duh, I should know better.

In my professional opinion, I really wanna say it could be from electrical surges. Like if you are running with the heat on full, lights on, and coming to a stop, and as soon as you come to a stop, the engine fan(s) kick on, the surge from all the juice being consumed could be causing poor spark form the dis. Only reason I sugges surges, is because when I had my mtx 8100d, 2200watts, running to 4 12's, if I was lettin the sounds slam, and was running the heat, with the lights on, and I slowed to less than 800 rpm when turning, the car would die. It didn't do it all the time, just here and there. Since then, I upgraded all my power/ground wires for the battery/alternator/main fuse box, and no problems whatsoever. Then again, it may be a sensor. Process of elimination.
 
Also check your motor mounts real good. The reason I say real good is you can't alway's detect a bad motor mount by looking at it. On my first motor mount change they looked fine, I even had a Ford dealership tell me they were o.k. After awhile I decide to change them anyway because I tried everything else to get the car to idle right. When I took them out the passenger side mount came out in two pieces. New mounts and the car ran like new.
 
I've seen several posts regarding engine mounts while researching my problem. How does this affect the way the engine runs-Does the engine ground thru the mounts? I would think that there would be ground straps on the car for this.
 
Yes, there are ground straps. They attach at the motor mounts, I believe. I don't know if that's the reason show mounts cause bad idle (I doubt it), but bad motor mounts can definitely cause a bad idle.

Dale
 
OK, assuming that I need to change the engine mounts, how rough of a job is it? Any recommended shortcuts? Also, does anyone know the real reason that worn mounts can cause idle problems, or is it just one of those automotive quirks that just "happen"? Is this just related to the SC, or do regular V6/V8 cars have this problem also?
Thanks, Mike.
 
Our cars develop so much torque and the mounts are fluid filled and tend to tear. Left unchecked could result in the oil pan rubbing on the cross member thus a hole will result. There is no easy way to replace them. I did mine a side at a time with all pumps in place. I did however remove the starter and exhaust. Some have removed the jack shaft and power steering pump brackets to get to them. It might be worth it to have them done if the price is right and you know the shop.
 
Bubble-city- have you figured out what it could be? I know it's not my mounts or IAC, nor is it electrical surges or a vac leak, and it's definately not the o2 sensors. I just replaced the o2s and my gas mileage went from 200 per tank to 93 miles on 3/4 of a tank :confused: Let me know ifyou figured anything it might or might not be. Maybe we could have each other a little money.
 
This recently happend to me a single time. I recieved indication that it could be troubel from the cam sensor. Determine if you have a small coolant drip somewhere like the thermostat housing, and look for contamination of the Cam sensor. The coolant will apparently quickly cause malfunction with this and the crank sensor. It seems to me if this is happening regularly it could be a timing issue, and one of these sensor could cause that.
 
Well I finally gave up and brought her in to the shop. They said that the computer is fried, possible from the Jerry chip that was installed. Not sure if you fig out what was wrong with your car Bubble, if not you might want to take a look at your computer.
 
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