Thread: No Power thru my shifts.

Purchased my daughter a 01 grand prix 3.8 101k. Car seemed great but we know how teenagers drive tsk tsk. Last week she came to me saying her car was running poorly but I'm sure it has for some time. O figured I would fix it and if I couldn't I'll take it to the shop. First thing when o took it for a cruise. No CEL. It stumbled thru the gears. Trans seemed to kick it when it could. But I would REV without getting much speed or power. Car would top out at 50ish. Sometimes o could get it up in the 70s and 80s but without any power. Thought Trans or Cat failure. Decided to unplug the battery and see if codes would reset. Came back with EGR fault. Took it off and cleaned it. Came back with random misfire and o2 sensor. Found a vacuum leak in the manifold. Sealed it up then codes went away. But still have the issue I had before. Anything else I should look at before I take it into the shop?

Sorry to ramble. I think the code for egr was 0401. I ended up cleaning it out with carb cleaner and unplugged battery. Heard a leak in the manifold. Something melted on it near the throttle body. I used a plastic welder I also changed the plugs and wires. Codes for the random misfire and o2 sensor cleared. But still have these performance issue. It could be transmission related. It's a non supercharged 3.8. The rpm gauge seems to rev higher than it should without the increase in mph. I can't redline it tho. Speed comes to a halt around 50 mph. I can get it up to higher on the highway but takes a long period of time. It doesn't have power to overtake any other vehicles. I haven't found any stored codes or what not.

So far no codes a few e being thrown the car has not much power took it to the shop. They looked at it and wanted to replace the entire exhaust for about 1k. They said the flow of the cat seemed good bc of the in and out temp and they thought maybe something was plugged up downstream. Might try and take it to a exhaust shop and see if they can figure something out. They also checked the fuel pump and some other things and said it all came back fine...

How about just disconnect the exhaust after the cat and see how it runs!

If it runs good after the disconnect then it the exhaust.

If it runs bad after the disconnect then your back where you were and didn't spend 1K for an exhaust.

Ok got a shop to look at it they said fuel pressure was good but there was back pressure at bank 1 o2 sensor I'm gonna try and get that cat out and will try your advice. I'll probably start pricing Dow pipes and cats any recommended options?