Land Rover Repair: power loss at 70 MPH, carbon buildup, filter line

Question
Hi! 1998 Disco LE. When travelling about 7O MPH I have sudden power loss/surge. I had the TPS replaced, this worked for a few weeks then began again. Next they recommended I have my transmission flushed, did that, no results. Often happens if I'm on a long trip, then stop to get gas, or food. When I get back on interstate its pretty bad, then finally kicks in. Pretty frightening to say the least! Any advice would be greatly apprecaited!

Answer
Hi Jason,

I know of a few causes that can do this.  The first to come to my mind was the exhaust valve sticking problem.  Usually give same problems as you describe.  Starts when engine is hot and on hot, humid days and long trips.  Exhaust valves stick due to carbon buildup and the only fix is a valve job.

Mass Aif Flow (MAF) sensor ($$$) can trigger this type of reaction when it starts to fail.

If your fuel filter, line or pump is fouled, it can cause your engine to hesitate.

I've seen the TPS fail on my Disco but it's symptom was generally rough idles and wildly swinging surges at idle.

I hope this helps,

JohnMc