Hello all,

I got a '91 dodge daytona shelby (turbo) with 5-speed manual.

Here's what I need help with. Lately in cold weather I began having issues with stalling. I have a speedometer that is faulty and sometimes it takes a long time for it to come on, sometimes up to 20 mins worth of driving. Recently in cold weather, stalling became a problem. Whenever I have to stop for a stop sign or a red light and shift into neutral or just press the clutch to down-shift, my RPMs plummet down to 500 RPM and it would often stall. I noticed that the car only does this when the speedometer hasn't turned on. Once the speedo has come up, the stalling issue is inexistent and the idle is regulated fine around 1K RPMs.

The computer codes show code "15", no signal from speed sensor.

Can the faulty speed sensor have impact on idle stability when the car is moving? Note that it doesn't stall when it stands still and idles - only an issue when I'm in motion.

What's the fix to this? Is it something I can do myself? Is there some connection I can check? Where is it? I'm not very competent under the hood but can find my way around if enough directions were given <img border="0" src=smileys/smiley4.gif border="0">

Thanks for any comments... This is a very annoying problem.

Denis<edited><editID>deniss</editID><editDate>37969.4501157407</editDate></edited>

My '88 Daytona Shelby Z has had the same speedo problem since the day I bought it(used). It works when it wants to, it will kick in or just quit at random at any time. I never bothered to check into it, because I learned to read the tach to determine my speed. It would also have an RPM drop like the one your refering to, but it was also at random. Mine never stalled out due to this however. Check to make sure that there aren't any vaccum leaks. It may be possible that there is another sensor acting up at random, like your speed sensor. By the way, most of the time when I would do a computer self check it almost never gave a speed sensor code or any other codes.<img border="0" src=smileys/smiley5.gif border="0">

thanks for that... yea, i am beginning to think that the speed sensor may only be a part of the story. come to think of it, there were times in the past, like 5 years ago, when the speedo would act up and not turn on and the car would never encounter an unstable idle.

at the ALLPAR website, some people described exactly my problem and said it is due to an ill speed sensor or a bad connection with one.

you are right though - there might be more to the problem than just that. a car should normally be able to recover from the drop in idle, i would think - i never had the stalling problem in the past, even though speedo would malfunction in the past...

could it be an idle speed motor or whatever it's called? maybe vacuum lines... vacuum lines give the weirdest problems of all and the most annoying ones......

Yes, check for a vacuum line leak. It has been a few years ago, but a vacuum line came off that went to the charcoal canister and the car would start up just fine then just fall on it's face and die. Vacuum leaks are a pain in the <img border="0" src=smileys/smiley35.gif border="0"> . Also go through and make sure all of the sensors connections are good and clean. But, as I mentioned, it could also be a sensor that is functioning improperly like your speed sensor.<edited><editID>71ROADRUNNER</editID><editDate>37971.1588657407</editDate></edited>

but vacuum is pulling a healthy 25-30 on my vacuum gauge... the
car doesn't just stall - it only stalls when coasting to a stop in the
neutral or when depressing the clutch, and that only happens when my
speedometer isn't working. when the speedo is up and running, it
runs just fine.



anyhow, i had the speed sensor replaced - will let you know if that fixed the problem.

I hope that solves both of your problems. If it solves the stalling problem that would be great, but it would also be a shock to me because I don't see how the computer could link one to controlling the other. <img border="0" src=smileys/smiley5.gif border="0"> These Shelby's still never cease to amaze me. <img border="0" src=smileys/smiley4.gif border="0">

Okay..... If it only stalls in Neutral, or when the clutch is in, which would in turn be around the same time usually, it very well could be your clutch cable... It may be pulling, and causing your clutch to disengauge when it isn't supposed to, causeing your RPM's to lower, and stall!

Is it running rich? I found a vacuum leak in mine that cured the stalling issue when coasting to a stop in neutral. Make that leaks plural[:@] Plastic and heat equal fatigue and cracks. Good luck!