2000 GT driving issues

[EskyGuy29]

I recently have been dealing with a stumbling issue with my car. No closes but I hooked up
My scan gauge to see if I noticed what was happening while it stumbles. It seems to happen at highway speeds (65-70) and notice a hesitation where if I give it some acceleration nothing really happens other than a stumbling. Rpm doesn’t drop much but noticed twice now that IGN timing is reading 18 and will not go higher or lower. I forgot to add that this is under little load and in 5th gear. If I down shift it seems to “snap out of it”. The car is stock for exceptions of mufflers and a JLT short ram air intake. I can’t think of anything that I have done to make this happen. It does have new COP packs as well as new spark plugs (e3). Any ideas folks?????

 

[wmburns]

Your problem could be caused by a bad alternator diode. Start by ruling this out.

Howto perform charging system voltage drop test

Howto perform charging system voltage drop test

To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...

www.stangnet.com

If you are positive there isn't an ignition problem then what have you done to rule out clogged fuel injectors? I have had great luck using an injector cleaning and flow test service such as InjectorRX.com. Once cleaned and tested they are as good as new (but cheaper). The before and after report can help you figure out if you are on the right track.

 

[OneSick99GT]

Pull the codes and post here. If your car has over 100k miles I would replace the the fuel injectors. Since you have new ignition coils and spark plugs the injectors or one injector could be the issue. It might not be bad enough to throw a misfire code yet. Pull codes and replace those injectors. Replace the fuel filter then check fuel pressure.

 

[Danny2v]

Don't always trust new parts, I had a misfire long time ago and I bought a full set of coils from AutoZone and replaced them all, 2 months later I'm driving down the freeway and if I put load on the car at lower rps, I would get a death rattle. No codes no lights so I was stuck figuring it out myself. I said might as well change the coils again because AutoZone has a lifetime warranty and sure enough the problem was fixed. Just a thought I guess. Only other thing that may run through my mind is a clogged fuel filter or a weak fuel pump but I would imagine that would cause stinking constantly rather then a specific speed or load

 

[TeamCaffeineGT]

Monitor your fuel pressure. Might just need a new fuel pump.