Does anyone know where I should start looking for a small stumble. It only happens from a dead stop. When you press the gas is just stumbles a little. Kinda like it wants to quit. It has never quit though. I have a 1987 XJ6 with 82,000 miles and a 4.2L. Just did a complete tune up and changed my fuel filter. Thank you in advance.

 

Cold engine? Fully warmed up? No difference wither way?

One easy stepping off point is the throttle body. Make sure it's clean as a whistle and set to the proper .002" gap. If you need details with that, post back

Cheers
DD

 

To add further to Doug's questions . . .
Did this "stumble" exist before recent tuneup, or appear after?
Any change after tuneup? Better? Worse?
+1 to DD's advice on TB.

Cheers,

Ken

 

It doesn't matter the engine temp and it doesn't stumble every time. Sometimes I can drive all day and its perfect, then the next day its just the opposite. Not sure about the before. When I got it it was flooded with gas so I did a complete tune up before I started driving it.

 

That obviously makes it more difficult to nail down. The 'could be' list might get a little long.

Clean the throttle body and, while you're there, carefully inspect the ducting from the Air Flow Meter to the throttle body. Is it loose, cracked?

Carefully inspect/clean/tighten all connections and wires to the AFM, coil, ignition module, and firewall relays

Cheers
DD