revs fluctuate when idle.. - Hyundai Performance Forums

figs · 01-28-2007, 02:33 AM

Instead of idling at about 800 rpm the cars rev oscillate between about 600 then up to about 1000 revs once every second or two. This seems to go hand in hand with the occasional drop in power when driving (as if I've taken my foot off the gas) for a second or two, then it goes back to normal. Usually does all this AFTER the car has warmed up a bit. Has done all this once before but was fixed after going for a long drive. Car also pings under acceleration at around 3000 revs but has been doing this for years

Any ideas on what would be causing or how to fix this?

(manual 97 lantra)

wilburisthecoolest · 01-28-2007, 03:05 AM

Bad idle control motor.

Could probally just clean it up with carb cleaner really good.

Mine took a crap on me one day and it was like the pedal was stuck open, it just would rev well, and ick. everything.

accent0002 · 02-01-2007, 10:59 PM

throttle positioning sensor on throttle body maybe mine had a loose wire in the back of the sensor i pushed it back in and was fine dunno if urs is gunna be that easy

dreamriver · 02-02-2007, 11:08 AM

also check vacuum leak at throttle body and IM area... with TB cleaner

figs · 02-13-2007, 09:26 AM

throttle position sensor resistance seems fairly normal..

IN4PAYBACK · 02-15-2007, 05:16 PM

check your entire air intake for any loose fittings and or leaks. when my cai came undone, my hp went to **** and it idled really high.

if you have a car alarm, you may not want to do this since it may reset your alarm and you may have to take it to the dealer to have it reset, im not really sure if your car is like my tibburon.

unplug the battery. actually, only one side, i think its the negative. whichever one looks easier. let it sit unplugged for about fifteen minutes. plug it back in, and start the engine. make sure all lights are off. keep the car in neutral, do not tap the gas or the brake (use emer. brake to keep car from rolling) and let it run its course for about five minutes. this will reset your comp. and may take care of the problem.

dreamriver · 02-24-2007, 07:54 PM

check your coolant level in the radiator

figs · 03-03-2007, 09:19 PM

hmm some total fuel system cleaner and a good drive seemed to fix it... a cheap repair.