Removed the cat, I cut it off before the downstream O2 sensor

 

With the cat cutoff you probably would have gotten a P0420 code and possibly others as well. Codes from p0137 to 141.

 

Ran my reader on it and a mechanics portable reader on it and they both only show the oil pressure switch malfunction. I am going to start doing ohm tests on the sensors tomorrow to see if I can find one not functioning. Any thing else you can think of would be appreciated, thanks Keith

 

Ok I worked on the car this morning found nothing, I put about 30 miles on it trying to get some kind of code to come up, just put the scan tool on it and got 4 codes...C1276 torque signal malfunction...P0122 throttle pedal position sensor A low input....P1122 throttle position sensor circuit low intermittent....P1189 engine oil pressure switch circuit. So is any of these codes possibly be my problem?

 

The only code I would think that would cause the problem your having is the oil pressure switch but I'm not a mechanic. I know it's aggravating, I have taken off your air intake and manually worked the throttle?? Wonder if it's not going wide open when you give it more gas? Multiple problems are tough.

 

KK525.I had the same problem with my 2002 Monte Carlo. I had the cat replaced, and I replaced both O2 sensors. It ran great again. I feel that you must have the cat and O2 sensors in place or the computer will keep sending the car into LHM. Limp Home Mode. Hit me up if you need more help. I forgot to mention that when the cat was failing I got no check light or codes. Nothing. The car just ran terrible and it was in limp home mode.

 

Ok I replaced the oil pressure switch, running a little better, it revs up to 3000 rpm before it cuts out now, ordering a new cat and 02 sensors tonight, hopefully that will fix it. I rechecked the codes and they are all gone, but for some reason the security light comes on then goes out. Hoping this isn't another problem.

 

Check the o ring on the pcv valve then the one on the back of the uim, if they are broken or leaking, including the hose to the brake vaccum cannister or the fitting it will run like a dog. If you get a big enough leak, it will start to idle then cut off with a a few chuffs and maybe a backfire. If those are okay, go to the egr valve and see if the poppet is sticking open or not functioning. There is also a wire bundle that runs up the back of the engine by the passenger side rear lift bracket, the wires are very thing there and may break when the engine is rotated forward. If okay, take a look at the wire harness from the crank position sensor and follow it through, it may be chaffing on the block somewhere. After a while, the wire protective coverings deteriorate and may contact a head and burn then ground out. Also check anywhere the wire bundle may be loose and rubbing against metal. good luck

 

Ok put new cat on and both o2 sensors, car will rev to 4 grand if I feather the gas then acts like it hits the rev limiter, if I jump on it it bogs and won't go past 2300 rpm, I replaced the MAF sensor and checked for broken wires and vacuum leaks and could not find any. I do not have any codes now, I have checked it several times with different readers. Could it be the computer doing this or something else. If the car is in the limp home mode is there something I have to do to get it out of it or will it turn it off when I finally find what's wrong with it?

 

I had that problem a month ago and it was the cat. converter.