Sometimes when I am driving at a steady MPH my car will sometimes feel like it will almost jerk or hesitate. It will sometimes do it like 4 or 5 times in a row then it runs fine. Anybody have any suggestions? I know it is time to change the plugs and fuel filter. My jag is just shy of 90,000 miles. Thanks!

 

cue, it's well past the time for new plugs, air and gas filters. Clean the MAF sensor and Throttle body as well. Hopefully this'll cure the surging while cruising. If not, she may be having misfires possibly due to a failed coil.

 

If your engine still has the green or yellow label coils, you need to replace all of them with some later parts from Ford or Jaguar (same as the 3.9 Lincoln V8).

bob gauff

 

Great guys thanks! I bought her with 88,000 miles so I am not sure when the prevoius owner or even if he changed the plugs. I will do pulgs and coils for sure.

 

KY generally works...

 

KY jelly? LOL! Bob, the OP inferred he's likely experiencing low fuel pressure or misfire...not friction incurred during you know what. Jeez...some guys?

 

I had a similar problem with my V8 at around 50 mph, I recently fitted a new set of coils and it runs fine now

Another forum suggested that the coil packs should be replaced @ 70 thou miles - mine has 86 thou on the clock.

 

I thought that comment would come!! LOL. I looked the coils and they had a yellow sticker on them. I told my friend at the auto part store to order some for me.

 

Who's Bob? I was downstairs playin' the piano...

 

here we go again... lol