I have a 94 Silverado 350. It has started hesitating and even went dead 3 times thus far. Rpms drop when accelerating. Catalytic converter is broke loose per muffler shop new muffler. No cat still on but not useable. Pull code says o2 sensor. Any Help?

add new cat and o2 sensor - clear codes and see if it returns

Would the bad cat cause it to stall? I read on here that it could be TPS. Is there away to test.

Would the bad cat cause it to stall? I read on here that it could be TPS. Is there away to test.

you may need to check fuel pressure when it does this,i have replaced afew in these trucks

I drove it home this morning only seems to drop when you take foot off pedal at coasting speed. Then accelerate speed. Runs at 1500 RPM then drops to 1200 or less. How do you check pressure?

with a fuel pressure gauge some parts stores have a loan atool program check before buying some systems will have a valve on fuel rail on intake others you have to tie into system at a breaking point say like at the filter etc,

The O2 code is most likely caused by the fact that the ctalytic converter is disconnected. Sensors can't get a good read on the exhaust--it goes by too fast or has oxygen entering from other sources (i.e., uncapped exhaust pipes, high flow mufflers, etc.)

When the engine stalls, what do you have to do in order to get it running again?

I have to give it alot of gas. This time the oil pressure is dropping when RPM's drop. It went dead 8 times each time having to pump pedal. Shooting black smoke out the tail pipe. I had to wait till RPM's stabilized to give it gas if I didn't it would just go dead again. I have changed the plugs,wires,air filter,fuel pump, and replaced vaccuum line at MAF sensor. Any help would be appreciated.

Sorry I replaced fuel filter not pump.

go back to fuel pump / pressure test.

Have a shop with a good scan tool to view the O2 sensor reading as the engine is running. Sensor is most likely sending a lean mixture signal to PCM, which in turn tries to richen up the mixture, which floods it out. Also, check for (major)vacuum leaks. Drive the vehilce with the fuel pressure guage attached, note pressure when engine starts to die.