I have a 2000 Chevy K 3500 Ls with 7.4 vortec it has a running issue when parked if u floor it. It will not rve above 3 grand but if u ease into it will rev all the way up and while driving it it wont rev above 2500 rpms but it will straighten out than will run fine both driving and in park i changed plugs and wires distributor cap and button and new fuel pump and filter cats are removed because of being clogged and just ran pipe has small leak where donut gasket is working on replacing it scanned it and say bank one lean did live feed test and noticed O2 sensor has volts when running good when it acts up it bank 1 O2 sensow losses all volts.

 

I'd run a scan on your fuel pressures regardless of the new fuel pump or not. It's either not getting enough fuel or air. The fact that your converters were clogged leads me to believe that your motor ran too rich or you have motor oil that was being burned in them. Those are the main reason cat-cons go bad. Lucky that you live in a state that allows you to run without them, in fact. Might want to clean your MAF sensor, but I don't believe that is your problem.The O2 sensors might well be since they might be dirty, or not operating properly, from what destroyed your cat-cons.

 

I cleaned MAF sensor no change havent got a fuel tester yet to check fuel pressure would the O2 sensor cause that big of a problem?

 

Yes they can. I didn't think the MAF sensor was your issue, but it's good to keep them clean