hi. i have a 1988 xj6 and am having a difficult time with it. it starts and idles great but after about 5 minutes of driving it will not respond if i try to go over 1500 rpms it bogs down and then surges and bogs and so on.i have replaced the maf fuel filter and checked the fuel pressure whixh is fine.but it hasnt changed anything. i am not getting any codes or warning with the exception of power fluid level low. i cannot figure it out only thing left to do now is maybe the ecu but as i said its not kicking out any codes. does anyone have any ideas as to what the issue may be?

 

that sounds like a bad coil to me. theyre cheap and easy to replace so its worth a shot. Next I would replace the cps, it couldnt hurt to have a spare anyways. Lastly i would say ignition amp(attack it with some electrical cleaner first). Also check earth points and make sure you have correct battery voltage, but an ecu is unlikely they tend to not fail very often.