1990 Mustang 5.0 Rough idle and Shuts off

90stangdemon · 10-04-2009, 06:31 PM

Hey I have a 1990 5.0 and I was wondering if anyone knows what could be wrong just need a couple ideas to see what I have to work on, in the morning when I first start my car it shuts right back off, i have to hold it to about 1.5k revs for a while until it catches on and then it stays on and I let it warm up, and the other problem is when I stop at red lights and I hold the brakes it jumps back and forth like its wanting to go already. I have to push really far down on the brakes for it not to jump. I have no idea what the problem is. Any feedback would help, please and thanks.

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Arostang · 10-04-2009, 07:32 PM

throttle position sensor?

90stangdemon · 10-07-2009, 02:21 AM

Yeah i'm going to go check out my throttle position sensor, i read about it online and my car has all the symptoms of a bad one, thanks for the help.

STROKED_LX · 10-07-2009, 03:41 AM

is it misfiring?

Mines doing the same thing but its also misfiring, runs like crap right now. Im tryin to hunt the problem down.

89stangbanga · 10-07-2009, 11:51 AM

Quote:

Originally Posted by 90stangdemon

Hey I have a 1990 5.0 and I was wondering if anyone knows what could be wrong just need a couple ideas to see what I have to work on, in the morning when I first start my car it shuts right back off, i have to hold it to about 1.5k revs for a while until it catches on and then it stays on and I let it warm up, and the other problem is when I stop at red lights and I hold the brakes it jumps back and forth like its wanting to go already. I have to push really far down on the brakes for it not to jump. I have no idea what the problem is. Any feedback would help, please and thanks.

What is your idle set at? What's your timing? AOD or manual? and What type of Cam shaft? If your idle and timing is correct, check for vacuum leaks for surging idle, clean the maf, throttle body, 10 pin connectors that look like salt and pepper shakers with electrical cleaner, check out your IAC sensor located on the throttle body looks like a tube, those are notorious for going bad. Then use di electric grease on all the connectors. If you want there is a idle surge checklist on forums.stangnet.com just do a search it's a post by jrichter i think that has every possible solution for the problem you are having.

mustang2427 · 10-07-2009, 11:53 AM

What type of Mods do have on the car? and is an automatic?

90stangdemon · 10-07-2009, 02:21 PM

Quote:

Originally Posted by 89stangbanga

What is your idle set at? What's your timing? AOD or manual? and What type of Cam shaft? If your idle and timing is correct, check for vacuum leaks for surging idle, clean the maf, throttle body, 10 pin connectors that look like salt and pepper shakers with electrical cleaner, check out your IAC sensor located on the throttle body looks like a tube, those are notorious for going bad. Then use di electric grease on all the connectors. If you want there is a idle surge checklist on forums.stangnet.com just do a search it's a post by jrichter i think that has every possible solution for the problem you are having.

Thanks for the help i'll definitely check out those forums, I'm going to do a tune up as well. But I looked at the throttle position sensor symptoms and everything that it says is basically what my car is doing. So I Might have to have a shop check that out too. My car is all stock except for an intake, and its AOD.

89stangbanga · 10-07-2009, 02:51 PM

Quote:

Originally Posted by 90stangdemon

Thanks for the help i'll definitely check out those forums, I'm going to do a tune up as well. But I looked at the throttle position sensor symptoms and everything that it says is basically what my car is doing. So I Might have to have a shop check that out too. My car is all stock except for an intake, and its AOD.

Oh ok, well yes I'm saying it most likely will be a tps/maf issue. I thought you had some mods done to it. Good luck with the fix.