Engine miss

[Brianpell]

Here is my issue. Have an miss/pop once in closed loop (basically anything after 1200 rpm) .I have just disconnected each injector one by one and noticed the engine stumble and rpm drop on each one every time. But, once any injector is disconnected my engine miss disappears. No pop from exhaust,no engine miss at all. No matter what cylinder I shut down it actually make the miss go away. Does anyone have any idea what the cause is or what I can look for. It's beyond bizarre.

 

[Nick Micale]

It is very difficult to diagnose an issue like this with the car in the driveway, but very difficult with a keyboard especially with very little data?

My approach to start would be to try determine and isolate if it is an electrical issue or a fuel issue.

Checking fuel delivery is rather simple, connect a pressure gauge to the rail and monitor it as the car gets warm.

A simple electrical/spark issue could handled a couple ways.

First, pull one plug wire at a time with the engine running to isolate a cylinder or 2?

Second, if a heat gun is available, check the exhaust temp of each cylinder while the engine heats up.

Third, pull all the plugs and examine them for oil, fouled, worn or whatever?

Working on a GN, or diagnosing them, requires some knowledge and common sense, an I phone and guessing is no match for common sense and some automotive knowledge!