2001 SS started to hesitate quite a bit. Found a cracked plug and switched it out with a new one. Had a little hesitation still until i decided to throw new plug wires on and had more power then i've had in a long time. Now, two weeks later i have no power. Idles and revs fine in park but once i step on it and get going, rpms jump up and engine lags horribly. It only responds to light acceleration and thats it. Not throwing any codes either. Im stumped.

 

Not sure but I had the same problem with a plugged Cat, but sounds liek your problems started with a different issue than mine hope someone can help.

 

I would check for a plugged Cat ..

 

I heard the 01's had issues with the cats. I'll will check it out tomorrow. There's been a definite change in tone too. Resonator started to peel apart in the middle and it isn't as loud as it would be normally.

 

You make it sound like this happened shortly after changing plugs and wires. By chance, are those BOSCH spark plugs in it? If so, change'em again. BOSCH plugs are JUNK in GM engines. I've had more then one negative personal experience with them. Waste of money and time.
BOSCH wires are fine, just not plugs.

Also, the '00 and '01 W-Bodies had an extended warranty on the factory cat due to a problem with the company who manufacturers them for GM. If you have the factory cat, that could be an issue. Sadly, I believe that extended warranty is no longer good (beyond the extension period).

My first suspect is:
- Plugs/Wires
- If the CAT is factory, due to the item I noted above, get it checked
- Clean the MAF sensor
- Ensure the fuel and air filters are good (change if unsure of age)

More then likely, it's something simple.

 

Yep, Bosch plugs. Fuel/Air filters are new. I'll try the plugs again and clean the maf sensor. If those don't work out I'll test the back pressure. Hopefully this will clear things up. Thanks for the help.

 

With the RPM issues I would say check your grounds as well. I had a problem like that and it was the culprit.

 

i'd make sure it's not a plug issue then i would check the cat.

 

I have a gut feeling those BOSCH plugs are your issue. Get rid of them ALL. Switch over to AC Delcos. Or, if you don't want to go AC Delcos, go NGK, but not BOSCH.

Once you dump those BOSCH plugs, if you are still having issues, look at the cat if it's still the factory cat.

 

Looks like I'll check the cat next. Switched the plugs out with AC Delcos, cleaned the maf sensor and unfortunately no improvement. I did noticed the upper intake leaking a bit near the egr valve but i dont think its enough to cause that extreme of power loss.