engine problem

[Robert Olah]

Hi, I need help with my jag. Every time I get to the 3000rpm he looses power and have to change gear because he start coughing. Still drive but can't go fast or pass the other car's. Please help me diagnostic this problem. 

[O.T.H]

Hi Robert --Welcome to the club and I'm sure you will get plenty of advice  -- I would say you have a fuel problem and think the 1st thing is to renew filter etc

 

Frank

 

[G.Mike]

Hi, new member here. I am having the exact same problem, but it isn't happening all the time. Listen carefully as I explain:

When I bought my X-Type 2.5 a few years ago, the first problem I had to have fixed was the Air Conditioning (groan). The problem turned out to be chewed wires from a mouse that took up residence in the engine bay. With that problem corrected, I moved on to other repairs. Then one day, the engine started cutting out at 3000 rpm. It ran perfectly until I got to that rpm and then just started sputtering and would not go any higher rpm. As soon as I dropped the rpm back below 3000, it ran fine. The next day, it ran fine. I could run through the gears all the way up to the redline. I did notice as I was increasing the rpm, that there is a surge of some kind at the 3000 rpm point, I am attributing this to a sensor or relay that increases fuel and or air to the engine at that time, much like the old four barrel carburetor when the secondaries kicked in. I can see where it might be fuel filter related, but wouldn't it happen ALL the time if that was the case, and not intermittently, as my problem is? Can anyone shed any light on this, or direct me to someone who knows what actually happens in the ECM at 3000 rpm to make the surge (or lack thereof) happen? Many thanks!