Need Help!!!!Please

I recently moved my 2001 Roush gt from being a garage keep car to it being outside and in the cold. I went to start it up and have never seen a problem like this. The muffler sounds really weird and the idle is funny sounding and it is almost like the horses are gone and I am pushing about 400HP. I drove it and in second gear i could barely get it to 30mph. My first thought was maybe the spark plugs. But it just sounds terrible and I need the car to drive. hopefully it is not something serious.

Is it shaking/vibrating? Any check engine lights? It may be sparkplugs...or one or more Coil-On-Plugs have failed.

slight vibration not to much but a little more than normal in the shifter handle...no check engine lights at all.

Well if it were a misfire, you'd definitely know it. It would shake noticeably around 1000-2000 RPMs. And I don't mean to be condescending, but does the CEL work? When you cycle the key ON, does the light come on for a few seconds and then extinguish? The bulbs can burn out.

If you can take it to an auto parts store where they can read codes for free for you. Even if the CEL is not illuminated does not mean there are no codes stored.

Thanks for the help and the bulb does work and I have a Tuner/code reader. I took it for another spin and the exhaust backfired a few times. still i am stumped.

Hmm, when was the last time you did a good ol' run of the mill tune up? If never, or you're not sure now's a good time.

All of the following can be done cheaply and in a parking lot with minimum tools:


Replace fuel filter
Replace air filter
Clean MAF using CRC MAF Cleaner
Replace spark plugs (be sure to torque these properly as the aluminum threads in the heads are known to strip if you over tighten)
Clean or replace COP boots and springs (check for holes, cracks, etc. Use a generous amount of dielectric grease on both ends of the boots/springs when re-installing)
Check all fluids for proper level and color


I assume you have the 5-speed manual. I've never owned a manual so I'm not sure on the specified fluid or maintenance for that, so be sure to consult your manual.