2002 Tahoe has a misfire at idle

[JohnnyK]

What's the fuel pressure when you make it run?

When was the throttle body last cleaned, and how does it look

What's the fuel pressure when you make it run?

When was the throttle body last cleaned, and how does it look now?

The fuel pressure is at between 50 and 55 when it's running. Hitting the the throttle makes it go up a little more. I have not cleaned the throttle body. It does have 2800,000 on it but it looks clean. I put Seafoam in it every other full tank.

 

[Fless]

So the KOEO fuel pressure is 58psi and the regulator is bringing it down to between 50 and 55 -- that seems like the fuel pressure regulator isn't bringing it down far enough. Others may chime in, but I think the running psi should be around 45.

 

[drdave81]

This code can be set by just about anything. Fuel, spark, compression or timing. You really need a scan tool that can read live data, or you're in the dark. You need to see misfire monitors to know what cylinders are misfiring and how bad. You need to see fuel trims to understand what kind of a misfire it is. If you can't see data, you can throw parts at it til you're broke. I'd suggest either buying a scan tool or just have it diagnosed. Once diagnosed, you can decide if the repair is something you want to take on, or have a shop do. But using a parts cannon is just a waste of money.