I just bought my 2002 Mustang GT. It has 62,000 miles on it, has the manual 5 speed and completely stock (or so I was told). My problem is that in the mornings (temp outside is in the 40s) when I start the car, let it warm up for about a minute or two, and go to take off it very sluggish and stumbles alot. Eventually it goes away and runs normally.

My thinking is that the beast is just a little cold blooded and I just need to let it warm up a little longer, but I wanted ya'll input too.

Thanks

 

ive always been told that the 4.6 loves to revv real high and run a lil hot

 

Check the MAF. It might be aftermarket or need to be cleaned.

 

Ok, thanks. I didn't think it should act that way. But once it warms up all is good. I will check the MAF next week when I put my new CAI on.

 

What CAI is it? That could add to your problems.

 

Mac

 

The straight shot?

 

Has it ever NOT started right away or had trouble starting? Kind of like bog down, but not stall, and then fully ignite?

If this is true, you might want to check your IAC and clean with carb cleaner. Common problem with 99-04 GT and happened to two of my vehicles.

 

Yeah, thats another possibility. Clean that and see what happens. If that doesnt work then give us the part number off your MAF. If thats stock, and the IAC is cleaned, then try cleaning the MAF next. Do everything one at a time, tiral and error.

 

wow, poor guy is having stang problems and you say that. Typical Jack. O well, at least I don't have a baby seat in my stang.

 

Not really an issue starting and idleing in the morning. And that is exactly what it is (a bog down). I can floor it and it bogs down instantly and then trys to catch up. After a few more tries it starts reacting to my throttle pressure normally.

Thanks for the tips.

 

Still try the IAC however, it certaintly won't hurt considering they're known to build up carbon. If you do not know where it is, it's on the front of the upper plenum and has a small cylinder looking thing pointing at you. There's only 2 small bolt's holding it into place. Just pop it off, spray some carb cleaner in it from the back and just work in it there the best you can. Also spray a little into the upper plenum around the edges and have that work in as well. Bolt it back on, start her up, and slowly rev it for a couple seconds. More than likely you'll see a little black/white smoke coming from your exhaust, but that's just all the carbon being burned off.

Another idea is trying a little sea foam in one of the vacuum lines to your plenum as well, this won't hurt to try either. Same idea here, burning off all the carbon that has been built up over the years.

 

These cars just need some time to warm up. Its normal to stumble when its cold in the mornings. Take that bend before the MAF on your CAI off and youll notice an improvement.

 

That bend is in no way a guarantee. I have BBK, a bend before the MAF and I've been through over 6 dyno runs and not once has my a/f been thrown off. In fact it was perfectly straight every time.

Now of course, sometimes the bend is a problem. IMO cleaning the IAC will be easier to do, so try that first, then modify your CAI.

 

Well, it's stopped all on it's own. I went and bought some seafoam to run through it (even though it only has 61,000 miles on it), but now I don't have any issues. I'm guessing it was the type of fuel I put in it last. I had filled up with 93 octane a few days prior to me noticing the issue. I read on some of the other boards that these stock GT's are tuned to run 87 octane. so the last time I filled up I used 87. Now a couple of days later the issue appears to have disappeared.

That MAC CAI is not the straight shot one either to answer your question.

Thanks for the comments guys.

 

our cars are supposed to do that. It's just the way they are. you shouldn't be romping on it anyways while the oil is still cold...

Think of it like a 'choke' on a lawnmower or weedeater...

this also happens with street bikes.

I really don't think it's the IAC because it would be having more problems returning to idle than revving..

anyways, i'm a noob and that's my .02

 

I'm not and wasn't "romping on it". I was simply trying to back out of my driveway when I noticed it stumbling. Like I said though, it hasn't done it the last two mornings (ever since I filled up with 87) so I think the 93 octane was causing my issues.

I'm fully aware that you don't just jump in ANY vehicle and start it up on a cold day (or any day for that matter) and just start hammering it before the oil has time to come up to temp.

 

what's the weather like where you are? I still think that has to be the issue. (I really didn't mean you were romping on it, i'm just extra careful)

Anyways, glad you found the problem. Hope it all works out

 

In the mornings it around 40 or so. I'm new to these cars too so I am still learning how they act to certain situations.

I hope that was the problem anyway.

 

I'm sure it was, that's how mine acts too. They just like beeing a lil warm before they start moving...even at half throttle...I always let mine idle for a good 30 seconds before i start moving (or till rpms dop below 1k) and then it doesn't se above 2500ish until completely warm....well that was before i blew the motor anyways

 

I'd be willing to bet the Seafoam helped out with it. Like I said earlier, it eats away all the built of carbon, and these stangs build up a decent amount.

It is also know that 93 octane can cause little running problems to a stock mustang, but nothing severe.

It's probably a combination of what everyone said.

And for your info, both my mustang's I've had had IAC problems with less than 40K miles.

 

Yeah, I talked to my mechanic (a good friend of mine) and we are going to clean the IAC tonight while we are installing the CAI and Exhaust system.

I hadn't done the seafoam yet, I had just bought it and then the Mustang started acting normal again.

 

were you referring to me? I didn't say the IAC couldn't be out, just that it shouldn't cause hesitation in revving...just at returning to idle...

 

No, I was responding to whitethunder in regards to me using the Seafoam. I was just stating that I hadn't had a chance to use it yet.

I understand your statement about the IAC, but figure while we are under the hood we might as well clean it.

 

and if you were talking about me, no, I was simply making a statement.

 

I didn't mean for any of my posts to sound rude or anything. Sorry if I offended anybody.

 

nah, you didn't offend me man. I'm just beeing a

 

Of course not. Ask as many questions as you want, after all it's your thread. Do whatever you damn please.

 

am glad I chose this site, you guys just help me with my problem,am having the same trouble with my 02 gt. thanks