[UNCFMM]

Hey to all, I know this is my first post on here but I am really desperately looking for some sort of solid answers here, as this problem is really holding me back from modifying my Mustang at all; so it here it goes, sorry for the length in advance, just trying to include all details.

Before I get any further though you should know that this vehicle had a little bit of baggage with it. The car was owned by an older woman originally but was stolen; the crooks abandoned the car and took off with just the rims and tires (the car was never wrecked during the theft/getaway). The insurance company finally paid the original owner back for the car but a few months later the car was found and now of course belonged to the insurance company. I'm assuming it was put up for auction so a guy who buys salvaged cars bought her but let her sit for about 2 years in his yard, doing absolutely nothing with it. So now she has the title of a "Total Loss" when you CarFax her but that's partly why I got such a good deal for it.

I bought a 2002 Mustang GT (automatic) with only 33k miles on it about a month ago with every intention to steadily make it a beast of a machine over time. I got to test drive it and had no problems, even goosed it since the owner was not with me and was shocked by the power it had (granted I was switching over from a '96 6-cyl Grand Cherokee) but the car gave me no problems whatsoever. Drove it home that night and spent about 10 minutes on the highway but still she showed no problems.

The day after I bought it I took it to a local shop and had the fluids vacuumed out and had new transmission fluid, brake fluid, new oil put in, and had the fuel filter (which the old one was disgusting) replaced. Also had the air filter replaced (also really nasty), everything else checked up okay.

The week after that we were going on a family vacation to the beach, roughly a 4 hour drive. However it took us around 6-7 hours to get there because we decided to let that great GPS tell us a different way to get there and miss traffic. I drove it all the way there and did not have a single problem the entire time. After our a week at the beach though, going back home was when everything started. We decided to take our usual route and were making good time, were looking at making it back in around 4 1/2 hours. However about 3 hours into the trip as I was trying to accelerate to catch up to my folks the car just started coughing hard, I slowed down to about 60 and then I tried to hit the gas again to keep up with traffic but it did not matter if I floored it she would get stuck at 3500rpm. When I let off the gas the RPM was sticking and took about 5 seconds longer then usual to start dropping, plus once it did start dropping it did so very slowly.

I eventually was forced to pull over and let her sit for about 10 minutes then for some reason she just jumped right back into normal driving like nothing had happened. The CEL was triggered but I don't think it was just from this though because it wasn't tripped until about 10 minutes after the car started acting up (took about 10 minutes longer of driving to reach an exit). So as soon as I got home I took the car to a friend and had him scan it at his shop, it came back saying the 5th cyclinder had misfired. He cleared and reset the computer and everything was back to normal. For about a month a drove her around the city and for the most part took it easy on her except for a few times when I could help myself and had to take care of some talkers. However she never hiccupped or anything during any of this.

About a week ago though I was driving my uncle down to a doctors appointment. The drive was about 1 hour and we were flying most of the way, probably kept it around 80-90mph for a good 20 minutes of the drive, and 70+mph at any of time however we got about 50 minutes through the drive and she started chugging hard again. She wouldn't get past 3500rpms and the RPMs were sticking again so I finished the 10 minutes off going about 60mph. Let her sit for an hour during the appointment hoping if she cooled off everything would be fine until I got back home. Not the case at all though... she never even stopped acting up even after that hour of sitting so I was forced to drive very easy on her and try to limp my way home. The dummy light never came on this time though. However I will tell you that I had to get some gas about 20 minutes into the drive though and just put about 6 gallons of just regular 87 fuel in there and after that she started purring again for some reason.

Made it back home finally and had her in the shop the next morning, they could never pinpoint a problem with it though so now I am again sitting here driving in the city with no mishaps but in the back of my mind I know if I take it out on the highway again for an extended period of time I'm probably in for a world of trouble. I have money to fix whatever it is but that's the thing, no one can figure out what the hell's going on with the inconsistency of the problem. I've pretty much eliminated overheating though because the guages never showed any signs and when I let her sit for that hour nothing on her seemed to be hot at all. I'm sort of hoping it's the fuel pump or fuel line that has some garbage in it and that's why it corrected itself after putting some fuel in there.

I'm really sorry for the length guys but just trying to include everything that happened through and through. Can someone please help me out here so I can quit worrying about if she will run right and start worrying about making her run faster.

[mell0]

well if you had a cylinder misfire maybe your plugs are bad. if its been sitting for a while without a plug change then something could have happened. and dont forget di-electric grease on the COP boots and plug threads.

[TempletonGT]

I'm new to these cars myself and no diagnostic expert but I wonder if there could be a problem with the #5 injector. Maybe it's intermittently clogging or not firing. Perhaps a good dose of fuel system cleaner and check the electrical connectors to all the injectors. Maybe remove them(the connectors) and reinstall them in case there is a little corrosion or something at the contact points.

Another quick and easy maintenance procedure that might be good would be to clean the MAF sensor, especially as you mentioned the air filter was filthy. Proper cleaners are available at auto parts stores. Handle and clean it carefully as the sensing wire is delicate.

Good luck

[UNCFMM]

Thanks for the responses guys, I did check the #5 injector for any corrosion but unfortunately there was none to be found. I also checked the spark plug but that also checked out okay, but I went ahead and swapped it out with the 6th cylinder plug so that way if the 6th cylinder gives me the problem now I'll know what the problem is for sure.

However, I took my car up to a local Ford dealer to have some body work done and while I was up there I went ahead and asked the head mechanic there and he said that even though I had cleaned out the MAF already it has a bad tendency to make the car run rough like I was describing if there is ANY gunk in there.

(I think I forgot to mention that the MAF had been cleaned out already, along with the throttle body, which was disgusting)

So hopefully I'll find the solution soon and be able to post it back here incase anyone else ever has a similar situation. Thanks again though, if anyone has any other ideas please let me know.

[charliesolhan]

If you had a 5th cylinder miss fire...then you need to check the plugs...wires and the coil...but i really doubt it is the coil...i would give here a complete tune up...then the idle sticking has to be a tps messing up..replace it w/ only motorcraft part...then you said you cleaned the throttle body out...you did know they had a special coating on them to prevent build up and your not supposed to use carb cleaner on it...just wipe it out...or sea foam is allright for it!!

[UNCFMM]

Well I didn't clean it out personally the guy at a local shop did it because I went ahead and got him to use the vacuum they have there to suck out all of the old fluids (I was feeling too lazy to do it all myself, I'll admit it) but I was watching him do everything and he never used any sort of cleaner on the throttle body.

However, thanks for the info on the special coating so if I ever have to clean it out again I know not to apply any cleaning solution. That's news to me for sure.

[charliesolhan]

Originally Posted by UNCFMM

Well I didn't clean it out personally the guy at a local shop did it because I went ahead and got him to use the vacuum they have there to suck out all of the old fluids (I was feeling too lazy to do it all myself, I'll admit it) but I was watching him do everything and he never used any sort of cleaner on the throttle body.

However, thanks for the info on the special coating so if I ever have to clean it out again I know not to apply any cleaning solution. That's news to me for sure.

No problem buddy...give that thing an overhaul and see how she runs then...then clean that maf...but if you said ya just cleaned it...check the maf wires and make sure there allright...then check that tps...make sure there is not build up...clean the maf and tps w/ some good carb cleaner or sea foam!!

[Kubie]

I don't know if this is your problem but I had a similar symptom with my 2000 GT. I was on my way home on the highway and all of the sudden I lost power. I floored the pedal and the car was bogging down bad. I could barely get 40-50mph. I had to run 3rd gear and limp home for 2 hours on a 30 min drive.

I took my car to ford and they found out that one of my catalytic converters was toast. It was plugged so bad the exhaust was forced through one pipe. Luckly they have a longer warranty for exhaust parts and put a new H-pipe with 2 new cats for me for free.

I dont know if this your problem but it is worth checking out.