Quote Originally Posted by harimon21 View Post
Driving a lancer 91 EFI. Lately may intermittent problem sya na di ko maintindihan. Naeexperience ko with more frequency lately na ung engine parang sinisinok and nagjejerk (di naman nagtatagal) kapag tatapak sa gas lalo kapag akyatin at mag-oovertake, then noticeable yung loss of power lalo na pag accelerating. Some days normal sya, some days hindi. Lumalabas yung sakit lalo na pag-long drive, seems ok on short level trips though. I suspect fuel pump, kase parang kinakapos at bagal umakyat ng rpm. Ok naman air filter, sparkplugs and no CEL is present. Some say might be dirty fuel tank. Ano kaya?

have your engine vacuum checked. it usually tells if the exhaust system is clogged, if the valve timing is off or tell you if the ignition timing is off but confirm with a stroboscopic tilming light. also check your ignition coil output. these should have been done when you had a tuneup specially it was giving you sluggish engine performance