I have a 2000 Trans AM 6 speed that I recently bought. Ran fine originally but has started idling rough and is very low on power. When I drove it home after purchasing it would spin the tires easily now it barely has any get up and won't pin you to the sit at all. Since it sat for a while I started by changing the fuel filter and spark plugs. I have also cleaned the MAF and throttle body. I have also reset the PCM. It has only had a MAF code when I unplugged the MAF while it was running. Since then no codes. Checked the cats and they are not clogged. I don't know what else it could be at this point except for the ECM. Any help or ideas would be appreciated.

 

these guys are going to want to know if you have anything aftermarket on the car, has the car been tuned, and are you able to log the car while this is happening, have you verified fuel pressure, have you confirmed all cylinders are getting spark, why do you think its the ecu? There is alot of things to rule out before you say its the ecu.

 

Yep, I agree with the above. It's very doubtful to be a PCM problem.

You have no codes so it's probably not spark related, but that's still possible.

I'd start by checking fuel pressure and/or fuel trim data with a scanner.

 

What scanner would you recommend to get the fuel trim data?

 

Have you verified fuel pressure is 58 psi or around that number? You may have something as simple as a weak fuel pump. Doesn't sound like you have diagnosed too deep.
go to your local parts store and rent a fuel pressure gauge and put it on your Schrader valve.

 

Start with changing/ checking the fuel filter first and then check the fuel pressure. With the gauge hooked up press the button for just a second to bleed off pressure. You can have pressure but poor volume due to a pump failure also. IF the engine dies instantly when you bleed it off even if the pressure is right or close you've got a weak pump.

There's very littleon the LS platform that will cause a low power no code problem. But what is always a constant on GM's of these years was fuel pump problems cars trucks and suvs.

 

I have not, I had a fuel pressure gauge but didn't have the appropriate adapter. Should be able to check tomorrow.

 

Update: fuel pressure is 5-10 psi at the fuel rail. Planning on checking at the filter to see if there is a drop. Otherwise planning on checking the relays for the fuel pump. Looks like I'll either have to drop the tank or cut through the top and make an access hatch.

 

Fuel pump relay either works or it doesn't; it's not going to lead to a low fuel pressure condition (only a NO fuel pressure condition).

Sounds like the pump is bad since you already mentioned changing the filter recently.

 

Change the fuel pump, 5 psi means the relay is working you fuel pump is just weak.