No accelerator response, progressively worse.

2003 Impala 3.4L

Thanks for any info. I have a very specific problem with detailed on information on whats been happening. Im just starting to learn about the PCM and its components so any info would be great.

Situation

1. Driving car daily, CEL came on and there was a very high pitched squeal from under the hood when at high RPM. Less power than normal and low gas mileage.

2. I was forced to run at high RPM because the car wouldn't maintain any speed at low RPM (would downshift). Driving the car like this one day, the engine was shaking very hard when trying to get it to shift and i could barely get to 80km/h. Eventually this caused the CEL to start flashing so I stopped driving immediately.

3. The car started and idled fine at home the next day without having made any changes.

4. Suspect plugged fuel filter / lines. Replaced fuel filter, run fuel inj. cleaner through. Problem still happening.

5. Suspect plugged Catalytic conv. Drilled a hole immediately before the Catalytic conv. and im currently driving the car like this. Car drives better than it was before doing this. The car still has less accelerating power than it did before, still makes the high pitched squeal when at high RPM but it doesn't shake and I can maintain 100km/h without over-revving.

I'm looking for any info on what could be happening. I'm not worried about upcoming emissions tests, as I just need it for the next couple months.
-Cut out cat completely and attach straight pipe?
-Problem solved a bit with hole in cat. but underlying issue involved or not?
-EGR valve? O2 sensor?

*Has never stalled once this whole time, idling or driving.
*Always idles well.

I don't have a diagnostics tool so any other diagnostic tips would be greatly appreciated.

Start by getting the codes and post back.

these vehicles are made with defective GM cat converters. big recall and replacement back several years ago.

what you do is remove the upstream O2 sensor/ leave the Hole open. drive vehicle ,,, vehicle has power,, then the exhaust is plugged up... that is your own personal diagnostic tool.

most likely the converter , could be the muffler as well. removing and inspecting will be the solution to this question you have.

when the converter is replaced make sure your plugs/ignition wires,coil packs,injectors are working good , because poor fuel burning will cause the new converter to melt down..

Hey thanks for the replies,

Start by getting the codes and post back.

Will be getting them shortly.

these vehicles are made with defective GM cat converters. big recall and replacement back several years ago.

Yeah I saw the recall, unfortunately it was after the 10 year period.

what you do is remove the upstream O2 sensor/ leave the Hole open. drive vehicle ,,, vehicle has power,, then the exhaust is plugged up... that is your own personal diagnostic tool.

thanks for the tip.. what will leaving the o2 sensor off do to the fuel mixture / egr? if u dont mind helping out a noobie

when the converter is replaced make sure your plugs/ignition wires,coil packs,injectors are working good , because poor fuel burning will cause the new converter to melt down..

If I can avoid buying a new converter Id like to.. its currently emissions tested and has a rotted out frame with 310K. Should i go to wreckers and grab a full exhaust / straight pipe or what?