4.3 Running rough

[RobL]

I have a 92 Sierra. 4.3. Running real rough when warm. Changed fuel filter. New plugs and wires but still runs rough at idle and accelerating. Runs fine at hwy speeds.
Any suggestions?

Thanks

 

[Schurkey]

When was the last "tune-up" services? Cap, rotor, air filter? Check ignition timing? Check cranking compression?

Connect a scan tool, look at the data stream.

What is the fuel pressure?

Perform a cylinder-balance test to find weak or dead cylinders.

 

[RobL]

Tuned up maybe 1000 miles ago.

 

[Schurkey]

Tuned up maybe 1000 miles ago.

Was it running properly then?

What about the other issues I asked about?

 

[RobL]

Was it running properly then?

What about the other issues I asked about?

I found it. One of the plugs wires was bad.
Thanks.