Yep, it seems odd to me.

Start the truck warm or cold, and if I wait 5 seconds or so, the CEL will flash 4 times, the rpm steps up to about 1200, and after a moment the idle crashes real low for a split second before returning to normal.

Otherwise no issues, truck runs fine, no stored codes.

If it is a warm start and I don't wait the five seconds before putting the truck in gear, nothing happens, and truck runs fine.

I've done some googling, but can't seem to come up with anything beyond the fact others have experienced this symptom, nothing comes back from FTE.

Any help or thoughts much appreciated.

 

?? Anyone?? Could it be IAC ?

 

Ok, realized upon second try that I wasn't doing the code retrieval correctly. Now I pull KOEO - 636, (TOT sensor self-test voltage out of range)
CM - 122, TPS voltage below .06 minimum
- 157, MAF went below .04 at some point in last 80 warm up cycles.

The very first time this occurred was after starting during a bad wind / rain storm. Starting to think something got wet.

I will clear codes and see if this returns.

 

my 95 was doing this right before the PIP sensor in the distributor went out and left me stranded,there was no code in the computer even though my truck would do the same thing as yours when the engine was started cold. After the truck left me stranded and I replaced the distributor to fix the PIP sensor problem,no more flashing check engine light,and no more funky idle problems at start up. Not saying this is your problem,just my experience.

 

I appreciate that cjben, I'll know what to tear into first if the rig quits on me. I haven't cleared the codes yet; wouldn't mind doing it without disconnecting the battery if possible - Trying to avoid the re-learn cycle as I prepare for the "sixlitre" tuneup.

I did adjust the initial riming back to stock (previous owner fiddled with it) a couple weeks ago. So disturbing the distributor and spout connector might play into what you mentioned about the distributor.

Thanks again.

 

Well an update on my progress.

Seems to me this might be related to the ISC-BPA (Idle speed control, Air Bypass combo) trying to re-learn the idle every time I start my truck.

The light flashes 4 times, and then the idle bumps up to 1500 (installed a tach on the weekend) for about 30 seconds, before plummeting to near-stall briefly, before recovering to the proper idle.

After that, everything is perfect. I'm at a loss as to why my truck feels the need to do this at every startup. No codes after clearing twice.

 

The high idle at start up is normal,mine does the same thing,has done it all 3 years I have owned it.

 

Mine will do the exact same thing on a hot start, accompanied by 4 flashes of the check engine light, and then a near-stall before recovering to normal, perfect idle around 850 RPM.

This is not normal, I have owned a few of these over the years, and they have not done it. It is the computer re-learning the idle, every time I start the truck, and I do not know why.

My next step is to follow the steps in this thread, and then I'll report back.

Idle relearning procedure.... - Ford Mustang Forums

 

sorry,I didn't realize it was every time you start the truck,mine only does it on cold starts.

 

Mine does the high idle on cold starts and what I call warm starts. It won't do it if its hot outside and its been running, but any other time it will do it for a few seconds. Its been this way since I got it in 99.

 

Yeah it doesn't matter on the temperature outside, or the engine temperature. Also it will do it right away if I shut it off after a long highway drive and start it again right away.

Haven't had a chance to dive into it again yet. I will post the results once I have the chance to take off the isc-bpa, and do the procedure I linked to a couple posts back.

 

Take it off to clean it that is..

 

I have a truck with the same problem The light flashes 4 times, and then the idle jumps up for about 30 seconds then almost dies then returns to normal idle.

 

mine does that accasionally on cold starts when it's cold outside like around 50-60 deg. when i start it the idle jumps up quick then nearly stumbles and dies before returning to normal. then after i drive it there is a whistling noise coming from the intake at idle in gear around 700 rpm. couldnt figure it out so i cleaned the iac and and disc. the battery(well battery died so i charged it slowly for 1 day). put batteyr back in and still waiting to see if it returns.
1996 f250-cc-4x4-7.5l-e4od

 

I tried everything short of replacing the ISC-BPA and it never went away.

I sold the truck recently, maybe the new owner will figure it out.