2003 Monte SS, 130K miles. NEW MAF and MAP sensor trying to solve this issue - no change. I also replaced the front 3 plugs and wires, still hoping to get the back three soon. Tried to replace fuel filter but it was rusted stuck and I haven't gotten it done yet. This problem has basically cropped up in the last 2 weeks. Car idles fine and steady, revs in park quickly with no hesitation. However, when driving - and MAF is plugged in - the car bogs down, stumbles and chokes on the slightest acceleration. I can't even get up a decent hill or press the accelerator more than a tiny bit. IF I have enough time and level road to get it up to HWY speed, when I press accelerator to pass or whatever the engine revs but doesn't downshift and revs uselessly while car slows quickly. I think it backfires as well, there's a definite popping sound/feel. If I unhook the MAF sensor it runs much better but not anywhere near normal and still can't go much faster that 60mph on the HWY. Revving issues still happens as well. I suspect CAT but some folks have mentioned vaccuum leak, TPS and EGR, etc. Any other ideas? I plan to replace CAT in two weeks but not counting on that to fix things and wondering if there's things I can do between now and then? Is having the MAF unplugged going to hurt anything besides CAT?

 

The MAF unplugged is going to make you run very rich, not great for the car.

Get that fuel filter changed and if you are already swapping the cat get that done.

That should do it for you.

 

Well, I had to cut the filter off and use a gas line repair kit but it didn't make any difference. I had a new cat put on, as well as a new upstream O2 sensor and it's like the car just rolled off the line. I haven't felt that power for a long time. Obviously the cat and emissions system has been slowly degrading the car's performance and I didn't really notice it happening. I can't wait to get it on the highway tomorrow! Thanks for the help!