Symptoms of "limp mode"

[LJRuddy]

Got in my car today and started it up. It ran fine until I shut it off to get some gas. When I turned it on, it was really hard to start. It started first but fluttered out. Cranked it over again and I had to go WOT for it to fire. After that, the engine would idle at 200 rpms and it would take some fancy gas pedal work to get it to speed up and I could not hold it at a steady rpm under 1500. The engine wouldnt even free rev past 3500 rpms. It was as if I was driving an ATX and it was in park. On the highway, the engine was very rough and I could hear misfires happening randomly. I also noticed I had to hold the gas pedal further down to obtain normal cruising speed. Got home and fought for 5 minutes to parallel park. I shut it off and tried to restart it. It started up fine and every single symptom was gone. What was this that I experienced? What might have caused it to happen?

 

[jthod]

Did you put deisel in it?

It better not pull that crap on Sunday! Maybe we do need a tech meet for your SHO.

 

[projectSHO89]

Pull your codes. You'll likely find a code for Coil A, B, or C. If so, your DIS module has gone south.

Steve

 

[SHOtime2511]

cam sensor anyone?

 

[Mr Anonymous]

"Limp mode" or "limp home mode" is primarily something you're only going to see in an ATX car. While the logic is there, it's very rare to see it in an MTX car, and you're more likely to have the car stall out and the re-start will reset it.

As suggested, you probably have a faulty ignition component.

 

[Devin]

When I didn't plug my TPS back in I had a really crappy idle and could barely get the car's RPMs up. Just a thought.

Check fuel pressure.

 

[projectSHO89]

cam sensor anyone?

Loss of the CID signal cause a zero tach reading.

Steve

 

[frosho]

Isn't it the crank sensor that runs the tach? I thought a bad CID will just cause hard starting and the occasional stutter on the road...

 

[Bizzy]

Isn't it the crank sensor that runs the tach? I thought a bad CID will just cause hard starting and the occasional stutter on the road...

No, the cam sensor runs the tach. It will also cause hard starting.

 

[SHOtime2511]

ive had a few that were going in and out where the tach still worked but would jump a little at times. most all hard starting issues are due to low fuel pressure or a failng CID.

 

[hawkeye18]

I recall on the V6SHO list a while ago we had a huge argument about crank/cam sensors, and Ford's various acronyms for such. CID, CMP, CKP, PIP, all sorts of stuff flying around, and we couldn't figure out what should be used for what. I say this because I've noticed that people seem to be using CID for both crank and cam sensors lately... not so much in this thread, but others. Just thought I'd bring it up.

As for this thread, though, I'd have to agree with the others; sounds like either a cam sensor or a failing DIS... DISs are sneaky; they can mask their failure in lots and lots of different ways. I would start with the cam sensor, as they're, what, $25? as opposed to $100something for the DIS.

 

[LJRuddy]

Well thanks for all of the replies! I will definitely keep them in mind. I have not had this problem since I first posted about it so I am thinking that it was a freak incident. (seems to happen a lot with SHOs )

I also just got back from the Kansas City/Nebraska SHO meet and from the looks of things, myself and maybe 1 or 2 other KC guys will be heading up to Jthod's place in August for a massive multi-car tech meet where I will be replacing my stock mounts with polyurethane mounts as well as my 24/26 bars, a complete brake overhaul with lots of shiny performance parts. I guess since I will be going this far, I might as well do a complete 60k while I'm at it. I will definitely replace the DIS while I am doing everything else.

 

[jthod]

It sure wasn't limping while you were racing Ryan, in Tijuana of course.

Damn his car smokes on shifts!

I also need to do a front 60k while we're at it. I've done the top 60k on mine, so I should be able to point you in the right direction, with SHOPP help of course.