multiple misfires detected, thoughts?

[inline]

Hey folks.

 

 

My bro has a 96 sierra, 2wd, 5000 vortec, automatic truck

 

 

He seems to be having a sputtering problem at cruise speeds.

 

 

He got a code, states, multiple misfires detected.

 

 

Hes done the usual maintenance, plugs, wires, cap rotor, coil.

 

I know this is a shot in the dark, any chance this is common with this engine/ model truck and there is a common fix?

 

Any thoughts?

[Norseman]

Has he done any recent mods to it like add an alarm system? What type of plugs are you using?

 

We need just a little more info than what you have given us. Did the thing just start misfiring out of the blue?

[Norseman]

How about trying to clean the CSFI injectors?

[mustang]

could be vacuum leaking around plenum. squirt carb clean around it. engine will change rpm's if so.

[GRB60]

Crank position sensor?

[mkimber]

My brother's pickup had the same problem and it turned out one of his injectors was bad. The hose that comes from the injector body had a small crack in it. But that was only on the #3 cylinder and the misfire code was the same.

[Lindsey]

2000 5300 was doing the same thing. Scan tool showed no sensor problems. I had been sitting on a fuel pressure tester for a solid year. Checked pressure using book as a guide. Ended up being the pressure regulator. $75. fix for a part the size of your thumb. Was easy to change though.