2001 blazer 4dr 2wd runs fine in park drop in drive and give gas and it struggles to go and miss fires . i hav replaced spider, coil, plugs,wires mass air sencor ,modual tps, and nothing seems to make it better any ideas

 

plugged cat.??
when it happened to my sister Monte Carlo SS it sounded muffled at the tail pipe

 

Any codes? Check engine light? Sounds like a MAP sensor, but I'm not sure if they still had them by 2001.

 

took y pipe off still does it

 

just went out and replaced distributor still the same

 

Have you checked fuel pressure and leakdown? Fast, easy and free to check it.

 

i have checked fuel presure and leak down

 

What was the regulated pressure, (key on, engine off, fuel pump activated) and what was the pressure 10 minutes after the pump was deactivated?

 

54 psi

 

Is that regulated or after 10 minutes? (check post #8 again)