Well, the EGR didn't fix it...what now?

[itsallhistory]

Hey Everybody,

My 91 V2500 5.7 4WD (4L80) has a power loss/hesitation problem at highway speed. I've replaced the Throttle Position Sensor, Plug Wires, Rotor and Cap, EGR Valve, EGR Vacuum Solenoid, Fuel Filter, PCV Valve, AND Fuel Pump. It's still got the problem. I'm stumped!! No Check Engine Light. Could it be a bad catalytic converter or a bad fuel pressure regulator?

The computer label has the following printed on it: 16154461 AWBP.

Thanks for any ideas.

Kevin

 

[Jims86]

Hey Everybody,

My 91 V2500 5.7 4WD (4L80) has a power loss/hesitation problem at highway speed. I've replaced the Throttle Position Sensor, Plug Wires, Rotor and Cap, EGR Valve, EGR Vacuum Solenoid, Fuel Filter, PCV Valve, AND Fuel Pump. It's still got the problem. I'm stumped!! No Check Engine Light. Could it be a bad catalytic converter or a bad fuel pressure regulator?

The computer label has the following printed on it: 16154461 AWBP.

Thanks for any ideas.

Kevin

whats your base timing set at?

 

[itsallhistory]

Unsure of that. I don't have a timing light.

 

[Jims86]

Unsure of that. I don't have a timing light.

You may want to see if a friend has one, or see if you can rent one from the parts store. there is a single black plug with a tan wire that you need to disconnect next to the brake booster, and Timing should be set at 0.
I didnt see fuel filter on that list, and if all else fails, I would say cat. Is it the original?

 

[itsallhistory]

I replaced the fuel filter. Yes, the cat is original. There is no smog pump on it so I guess the cat serves no purpose now anyway. Wasn't sure if it might be a bad O2 sensor. I've got a section of straight pipe and thought I'd go ahead and cut the cat off and replace it with the straight pipe tomorrow.

 

[itsallhistory]

I cut off the cat and put on a straight pipe. I'm crossing my fingers but I think it did the trick. I think it was the original cat so I'm sure it was bad.