Help gang, this morning when I started my truck it didn't sound quite right but it seemed to run O.K. I started up the street and it hesitated a little and the check engine light came on. When I got out on the main road I couldn't get up enough speed to shift to second. Around 1500 rpm, The whole truck started to buck and sputter. The really weird thing is, the flashers wouldn't come on either. Turned them off and on several times, and one side started to blink very rapidly. I know they were working fine because I used them this past weekend moving furniture for my parents. Anyway, amidst much honking and a number of people indicating I was number one with thier free hand, I got it home. I shut it off, checked the wiring harness on the computer, and made sure my superchip was still taped in place. I went ahead and tried to start it vroom, it fired right up just like it has since the day I bought it, no check engine light or strange noises. Could the IAC have been stuck? Combined with the flasher thing, I don;t know if it could have been a mechanical malfunction, or electrical. This is the first time this has happened and since the check engine light did not come back on, there is probably no way to check the codes unless the computer has error code storage of some sort. I have a '98 4.6 liter 5 speed. It has 74,000 miles on it. My only mods at this time are a superchip, S&B air filter, and dual exhaust. Cleaned and re-oiled the filter in July. Sorry for the extended post, but I wanted to get all the information I could in it. I would appreciate it if anyone had a direction to point me in. I'm a little mystified at the moment.
Thanks,
Rick

 

The IAC being stuck would have kept you from being able to hold idle without keeping your foot on the gas, but would have no effect on your electrical system. I would suspect your had some minor connection issue with the chip that you corrected while inspecting it.

 

It is most likely caused by the contacts in the chip. Remove the PCM and clean the contacts properly. Check the instructions that came with the chip Look at the contacts in the chip too. Loose conformal coating from improper cleaning can find its way into the chip contacts. A word of caution do not scrape the contacts too much so as to remove the metal coating.

Regards

Jean Marc Chartier

 

Thanks guys, will do as soon as I get home this evening.
Rick

 

Rick, it sure sounds like you had a bit of moisture on the Superchip contacts. I would recommend adding a light coating of electrical contact protectant, which dries to a waxy film and yet is perfectly conductive. It will prevent humidity or morning dew from causing this.

The blinker situation sounds unrelated, likely a bad flasher relay.


Moose
1998 F250XL 4x4
4.6Lw/5speed

 

I have not had it happen again. Everything seems to be working perfectly now. I left the windows barely cracked from the day before and there was condensate on the inside of the windshield so you may be on to something. Contact cleaner may be just what the doctor orderd. I have a can of LPS at the house. I think that's a great idea, definately worth the effort. I'm still slightly befuddled about the emergency flasher situation as they seem to be fine now as well.
Rick