Hey guys, I just bought my 99 GT last weekend and we bought it knowing that the engine needed to be worked on. When we drove it, then engine would surge at 1/2 to WOT... It is more noticeable in higher gears. It is almost like putting it in 5th gear while going 30 and trying to floor it... In low gears at high rpms it is not AS big of a problem but is still apparent. My dad and I think that it might have to do something with the fuel injectors or computer. We are hoping that it is not an internal motor problem which I am pretty sure it is not. The day we got it, I changed the spark plugs, oil, looked at the air filter but it didn't need to be replaced, and flushed the coolant(which was very thin and water-like...). We put some fuel injector cleaner in, and since it has not been AS bad as when I first bought it, but it is definitely still there.

I am just wondering if any of you guys have any ideas as to what it could be. I am hoping it is something that I can pinpoint and fix myself. If not I will take it to the Ford service center sometime soon and hopefully they will be able to fix it.

 

btw, here's an engine picture.

[attachmentid=10800]

 

The Maf sensor may need cleaning. To do this, go to autozone and get some electrical contact cleaner and you will need the Torx Security bits to remove it. Pull the maf sensor out and spray the wires good with the contact cleaner and reinstall it. Do not touch the MAF wires though.

 

Thanks Scott, I'll definitely give it a try. Also the car has 97,000 miles and I am thinking that close to nothing has been replaced/cleaned since purchased. Is there anything else that would need to be replaced after that many miles?

 

Hey guys, just an update...

I took the car to auto zone to get the codes pulled for the check engine light. It ended up being a cylinder 6 misfire. We changed the spark plugs about a week before, so I was pretty sure it wasn't that. So some people suggested it could be the ignition coil. I was going to get a diagnostics at Ford today, however they wanted $90.00 so I passed on that.

So today, I ended up going out and buying a new ignition coil for 40 dollars. I switched the old one out and started it up.... and it runs PERFECT!!! I was really surprised that all it needed was a 40 dollar part. The place where I bought it originally wouldnt go under 7,500 for the car. But because of the engine problem, they didn't want to fix it themselves and they ended up selling it to me for 6,700. They figured it was a big fix and they would end up just wasting too much money on it. So I pretty much got an insane deal on it!! I still can't get the huge grin off my face!!

 

Get the trouble codes from the computer.

 

Brad has had a bad problem with coil packs going bad. I know he's replaced at least 3 different ones. I wish I could figure out whats causing it.

 

On my 85 GT I had surging and it turned out to be the MAF sensor. It would drive me crazy. So when I read your article I immediately thought MAF; however, I do realize that the 85 Gt and 99 GT are entirely different engines. I wanted to know what a coil pack was??? and since you changed your spark plugs by yourself, is it easy? I am going on 90k miles and want to change them myself. THX

 

Coil packs are also known as ignition coils. When you go to remove your spark plugs, there is a covering that you must first unscrew and remove to acess the spark plug. The thing that you unclip from the wires and remove from over the spark plug is the ignition coil. There is one on each of the spark plugs. As far as changing spark plugs goes... I'm 16 and it only took me about half an hour to do it all by myself. You just remove the ignition coils and anything else in the way (such as the tb piping) and unscrew the spark plug and screw the new one in.

 

Thank you.

 

Wow!! Can't believe I may have found a solution to MY problem! My stang exhibits the same types of 'surging' problems as you! I took it to a mechanic and he did not know what's wrong with it. My 99 Gt, five speed, has only 57,000 miles on it. I replaced the spark plugs, fuel filter, decarbonated the intakes and fuel injectors, and put fuel injector cleaner in my tank. None of these seemed to help too much. The car will shake during acceleration, more-so in 4th and 5th gear and at lower RPM's.

But maybe all I need is a new ignition coil for $40! I was beginning to worry that it was an internal engine problem and would cost $2000+ to fix. I'm going to replace the part this week.