Crazy engine issue. Need help

[Dave884x4]

Ok. More or less, engine starts to stumble or miss fire without throwing a misfire code at about 3500 rpm. So bad you can almost not drive it on the highway. I have replaced the following parts.

Ignition module
Fuel filter
Plugs
Wires
Cap
Rotor
Coil
Cam sensor
Crank sensor
(had the cam and. Rank corilation set)
Battery
Had a new ECM flashed and tried that
Fuel pressure is good
New fuel pump.
I think that's all.
The only code it keeps throwing is a cam sensor fault I believe it was a int. voltage or signal loss. I going crazy here has anyone had this issue before if so please help.

[phipps]

I had issues with a misfire on my 97 GMC. I replaces cap, rotor, plugs, wires, coil and it continues.

It ended up being a worn distributor gear. Replaced the distributor and she's running great.

[j cAT]

that is a very good list of parts replaced. problem is what vehicle / year/ engine are you having issues with . that would help us figure out what is needed.

also provide what testing you did prior to replacing all those parts and if you or some other person shop is doing the work/troubleshooting.

when you post back with the details give any dtc failure codes and the measured fuel pressures.

give code numbers !

[Dave884x4]

Sorry it is an 1998 Tahoe 4x4 2 door
5.7 liter

[j cAT]

Originally Posted by Dave884x4

Sorry it is an 1998 Tahoe 4x4 2 door
5.7 liter

as a guess the distributor is most likely in need of replacement. after the fuel pressures are measured 60-65 psi .. then check for any rotor movement of the distributor. if you do get it to move then its worn causing miss fires and bad running at the higher speeds.

[phipps]

Pop the cap off and see how play the rotor has. I can't remember the exact amount of play that's acceptable but it's not much.