Stumbling from 40 to 50

[garbill2003]

Well I figured I would ask you guys for some input about this. Well it a 2001 gt 4.6 2v stumbles around 40 to 50 miles per hour. Has anyone exeprenced this problem with theirs? I've done all the spark plugs and ran some seafoam threw it. Next is the air filter and fuel filter. O and no it's not throwing any engine light's. That's the reason Iam asking you guys and gals

 

[mustangfan]

Could be a coil pack going bad. Sometimes they don't throw check engine light on and cause this issue. Might be a injector getting bad to. Just a couple of ideas. Your on the right track though.

 

[garbill2003]

Its been driven a lot and still no code I suppose I could go buy one new coil and do a switch for awhile till either it stops or doesn't. These cars aren't easy to work on if they don't throw a light at yah.

 

[Chief Gilly]

Try cleaning the MAF (CRC makes the cleaner spray). If out of ideas a dyno pull probably will uncover bad injector or bad coil or possible lean/rich condition. I got a dyno pull for HP verification for less than $100 and i found I had an injector going bad. A plus to that is you get to find how much HP and TQ you got.

 

[garbill2003]

Try cleaning the MAF (CRC makes the cleaner spray). If out of ideas a dyno pull probably will uncover bad injector or bad coil or possible lean/rich condition. I got a dyno pull for HP verification for less than $100 and i found I had an injector going bad. A plus to that is you get to find how much HP and TQ you got.

Iam going to do the mass airflow sensor tonight also a fuel filter and the throttlebody is getting cleaned