Idle surge then dies.
 

My car had been running great for awhile since I installed new heads a few months ago. Now just recently upon start up, it will surge pretty bad then die. But that only happens sometimes, usually after the car is warm. Other times it starts up fine but idles at 1100 rpms, them a moment later drops to 900 and is fine. I've cleaned the IAB and even swapped it with my other mustang and it still does the same thing. Anybody have any clue what is going on here?

Dirty MAF, fault in the TPS circuit, grounded O2 sensor, there are several possibilities. Have you tried to pull any codes?

I haven't checked for codes yet. I hadn't gotten a check engine light so I didn't bother, but I'll check tomorrow. My O2 sensors were new as of last year, about 10k miles ago. I cleaned the MAF sensor it didn't help too much. I did try taking the stock MAF sensor and put it on the Pro-M meter. The engine didn't surge nearly as bad, but ran very rough. The only thing I haven't tryed is replacing the TPS. I have a spare in the garage, I'll give that a try.

sounds like the infamous e-303 cam surging idle . is the crane your running the same as the e-303?

Yeah its the Crane version of the e-cam. Thing is though it was never this bad before. I can see if I had this type of surging when I installed the cam a year and a half ago, I could say it was the cam.

Just a suggestion, The 89 did this same thing immediately after installing a new TB, EGR spacer and K&N filter. I had to reset the computer to get it to quit doing it. Maybe it's having to relearn the fuel/air curve with the new heads. Also, it did it again the other night just all of a sudden like. After some head scratching in the dark I found the air filter has fallen off. You have a cold air kit. . .might the filter have fallen off?

Logically, that would make perfect sense, but we are talking about the infamous e-cam surging idle. it has baffled many a tuner.

I had the e-cam and the car would idle great at times, surge like a rabid dog at other times. The computer doesnt like the 110 lsa of the e-cam.

speaking from personal experience, i had the same problems you describe and I tried EVERYTHING to remedy it and nothing short of a cam swap worked. Maybe youll have better luck.

later

Maybe I'm in denial about the cam? I initally thought about the infamous e-cam surge, but was really hoping it was something else. I really don't feel like tearing down the motor again at this moment for a cam swap just to make the surge go away. I've heard that certian custom burned chips can help. Maybe I'll give "Tweecer" a try? Anybody had good luck with "Tweecer"?

yeah, a custom burned chip or something like the "tweecer" should be able to take care of it, but In my case, i wasnt happy with the e-cam so opted for a swap anyway.

Not sure about the eldelbrock heads, but my TW heads needed the longer threaded spark plug vise the stock length ones. When I put the stock ones but cooler in the heads I had bad surging, when I went to the longer plug for that head, no more surge. What kind of plugs are you running in your heads right now? When you did the head swap froms stock to the ones now, did you retain the same plug?

Yup had to switch spark plugs. I run autolite 3924's now cause of the longer reach.

doesn't the ignition module cause problems whenever its going out when the car is warmed up?

had the same problem tried everything iab, mass air the works and no codes after new o2's no more problem. worked for me.

The 02 sensors didnt work for me. I tired the MAF, 02 sensors, Idle air bypass adjuster from ford, all kinds of tuning, etc.....in the end, the cam change was the answer.