Jag xjr(supercharged) left for 2 wks,started ok runs fine but as it gets hot it wont rev very high,it pops and stutters like a missfire,holds back and has lack of power.If driven very gently its ok but put your foot down and it dies off and hardly goes.It is also drinking fuel worse more than it normally does.Coils check out ok,plugs are new.the only fault code is p1508(air something).

SOURCE: missfire

Locate you computer (right front kick panel) and tap on it with a pen while the car idles... Also flex it back and forth with your hands to see if the car runs rough or quits... You may need a new one.

SOURCE: 1998 Alfa Romeo 156 2.5 V6 86000 miles

reset ecu. turn ignition on. leave it for 90 seconds. turn it off and leave it for 90 seconds. start and run engine at idle for 15 minutes. dont touch the accelerator during processs

SOURCE: ford focus 1.8tddi lack of power

make sure the car is not running on the battery only and the alternator is good and all of the vaccum lines are good and they are on and ask yourself when was the last time you had a tuneup spark plugs and wires if needed and drivebelt and a fuel filter and a air filter.

SOURCE: 01' Jaguar XJR Starter location?

If you get just a click you should first check battery charge and all battery connections. The click is probably the solenoid kicking in but without enough battery to turn over the engine.