Intermittent Check Engine Light

glowstang93

20+ Year Stangneter :roc</strong><span class=
Feb 9, 2003
853
8
39
Illinois
About a month ago and this morning, when coming home from work, the check engine light came on. When it came on, I was going like less than 30 mph, so I gunned it and it went off. Then I noticed the rpms's were down less than normal when it came on again. Going to have my local shop check the engine codes on Tuesday. Any helpfule hints? I did some searches and saw it might be the DIS module. Does this really happen so intermittently? Thanks in advance.
 
Sounds like you have found the problem. The same thing happened to my 92 a few years back. I would be drivng and then lose power, give it some gas and back to normal. It will start to happen more often if you dont change it soon. Be sure to put some grease on the back of the new one when you replace it.

Dan
 
It is the ignition control module because I had the exact problem. The RPM readings are controlled by the ICM, and if the codes where 223/224, then it is most likely the ICM (DIS). A new ICM cost me about $110.
 
OReillys 189.99, Carquest 130.25 or 222.73, Napa 119 or 220.99.

Napa has the $220.99 in stock and on hold untill Tuesday when I get the codes checked. They said teh 220 one had better circuitry than the cheaper one.

Any more helpful hints?? Thanks
 
Check the coil packs if the ICM doesn't do the trick, expecially the primary. My primary coil cracked, caused a short that killed the ICM and sent the computer into fail safe mode and didn't allow me to really speed past 65, plus had a loss of power.
 
thanks tmx. At this point it doesn't have any problem going 0-85. I usually go like 73-75 on the interstate. If I pass on a hiway I could be up to close to 80 depending on conditions.

the only symptoms are the check engine light that came on and the rpms were showing 500.

Then the hint of hesitation around 40, if I stay at 40. If i go slower or faster, it goes away.

I really appreciate everyone's help. Keep the ideas coming, should have the computere checked monday or tuesday. for codes.
 
There was one case on the board where a person not only had a bad ICM, but also got an Injector pulse width too short code. Unsure how it was fixed, and I hope you don't recieve it, hopefully it's all just the ICM. An Irradic IDM signal, which would mean bad ICM, would be a code 223 or 224. If you get the code numbers, use these 2 images for reference to find out what they are if the shop doesn't tell you:
http://www.autozone.com/images/cds/gif/large/0900823d80194c9e.gif
http://www.autozone.com/images/cds/gif/large/0900823d80194c9f.gif
 
Well, it did it again this morning. I saw the tach jump from 1000 rpms to 2000 for no reason, then it went down below 1000 and the check engine light popped on. Not that I could tell you exactly what the tach is reading at every mph, but it sure doesn't look right. Going this morning to try to get the code read and hopefully solve this problem with a new ICM.

Dan is so right, the condition is happening more and more, it started a month ago just once, then last friday morning, now 3 days later it did it again. I can also tell the tach display is going bonkers :fuss:

Hope to post later today its all good :spot:
 
Yeah, I drove my car with a bad ICM for about a month and a half like that, happened more often and the tach was just haywire. Jumped around between 1500 and 3000 for 2 miles before deciding if it wanted to read half rpms or full rpms, it went with half. Eventually the ICM got to the point the car started to studder and die.
 
Well, the shop said it was the ICM. Codes 223, 224. Imagine that :rolleyes:
I went to go pickup the ICM from Napa and it rattled. Don't think that is a good thing :( . So tonight we are driving 35 minutes to Advance Auto Parts to pickup a lifetime warranty ICM. The guy told me $177, but the internet site said $128. I questioned it and they said if I brought in a printout of the site they would only charge the $128 :D So, sometime tonight I will put it in when I get back. I know, use plenty of grease on the back of it :)

Will let you know how it runs if it takes care of some of the hesitation its been having.

Thanks for all your help :cheers:
 
Its all fixed

Put the new ICM on and took it for a test drive. She idles smooth again, doesn't hesitate at takeoff or at 40 mph like it was. It was cool to see the mechanics look on his face when I told him that I knew what the codes were before he told me. :hail2: Thank you almighty 2.3 guru's