What's wrong with my 5.0 ?

mic_lx · Apr 4, 2008

It's been over a month now and we can't still figure out what is wrong with my 5.0 stang.
Heres some backstory. I was driving the car (not flooring it) and when I got to a stop light the car's iddle started to go up and down consistenly and it kept doing this since that day, no matter if it was cold or hot.

Had the car checked, at the shop they found that the MAF was damaged (I actually saw it, one of the wires was broken), also the IAC was damaged. They got both things replaced and things really improved but the car was now iddling at almost 1000rpms, but the idle still was noticeable to go up and down slightly... the only difference now is that when we turn on the AC, the car just dies.
We can restart the car again with no problems and no with the AC on the car will keep on running but the iddle will still go up and down.
They noticed this at the shop but this has been really hard to solve. They say that the TPS is good along now with the new MAF and IAC, so what else can cause this? :dunno:

By the way, the EGR is no longer working for this car, the previous owner took out the air pump and all the emissions stuff and was still running great.
Besides that mod, it also has a Cobra lower and upper intake, CAI and MSD ignition.
Any suggestions or ideas will sure help

riored96gt · Apr 4, 2008

Check the TPS throttle position sensor. They go bad. I used to carry a spare. Get them at the junk yard.

Mustang68 · Apr 4, 2008

well the iac was my first guess cuz a friend of mine had that go bad on his and did the same thing.. when he replaced it-it solved it..

im with RioRed96GT there... replace the TPS and see if that does it.. if not id look at that MSD as a possibility..

Mr. OAM · Apr 5, 2008

Does the car have any trouble codes? Might want to check that for an indication of where to start.

Steve

mic_lx · Apr 5, 2008

I checked the prices for new a new TPS, is not that bad and worth of trying since the car has been for so long in the shop.

How would the MSD affect (IF) the iddle and the car diying when turning on the AC?

About trouble codes from the computer, I dunno, the mech said there weren't any codes but I'll double check on that

Mustang68 · Apr 5, 2008

mic_lx said:
How would the MSD affect (IF) the iddle and the car diying when turning on the AC?

when i think MSD i think big red box mounted under the hood connected to the electrical system/ignition system..

is yours just the super coil or is it the brick like one?

main reason i said msd is cuz ya said its not holding a steady idle even when your not running the a/c.. to me if its not anything else id be looking at it.. cuz it is connected to the ignition and if its going bad it could cause problems in many ways.. unsteady idle could be one... i wasnt suggesting the MSD had to deal directly with the a/c stalling problem.. i was just suggesting it for the unsteady idle..

mic_lx · Apr 5, 2008

yeah the MSD is the big red box, that's what the car has.

mmh.. sounds interesting enough to give it a try too... run it with and without MSD and see how that reacts. So far that hasn't been tested.
I'll try those new things (new TPS and check MSD) and see how it goes, now I'm really starting to miss that car :crying:

95Grandtouring5.0 · Apr 5, 2008

If it's been that long and you can't find the problem, then do what we all hate to do. Take it to a professional.

Mustang68 · Apr 5, 2008

mic_lx said:
yeah the MSD is the big red box, that's what the car has.

mmh.. sounds interesting enough to give it a try too... run it with and without MSD and see how that reacts. So far that hasn't been tested.
I'll try those new things (new TPS and check MSD) and see how it goes, now I'm really starting to miss that car :crying:

yup just a process of elimination... and i know how you feel.. i miss driving my stang all the time too.. dont have anywhere to go and cant afford to go anywhere either...

95Grandtouring5.0 said:
If it's been that long and you can't find the problem, then do what we all hate to do. Take it to a professional.

yup.. i agree...

ScottyDsntKnow · Apr 6, 2008

MSD=Might Suddenly Die. I had a 6A box eat 3 coils on me before I was smart enough to put the J4J1 computer back in and bypass it. Guess what? The car ran fine. So I put my PIH/A9L back in and hooked up a Crane HI-6S. Worked like a charm.

The only MSD product I use are their 8.5 wires. I refuse to use MSD boxes or coils. I get Crane whenever possible.