Rough Idle

[The Rookie]

So over the past month or so my car has been idling funny, when i sit at a light it likes to jump between 500-800 rpm and shake, once i get above 1000 RPM its just fine, it stills pulls hard on the freeway does all the nice little things it usually does, but once i get to a light and the revs get below 1000, it starts to sputter like its gonna stall and i have to give it some throttle, I've already changed the fuel filter to a Z32 one checked all of my fuel injectors and got new spark plugs, whats weird is that it was doing this until about a month ago when i filled up (with what i believe to be) 98 octane at a gas station near the local track, funny thing is i didn't notice what octane it was until i put it in, I've checked for vacuum lines and i cant seem to find any, also i thought that maybe the fuel pump might be going out, could this cause it to have rough idle?

thanks for all of the help in advance.

[The Rookie]

no one?

[WWJD]

I've had similar problems. sounds like a vaccum leak. but this is what I did, I took off the IAA valve (unit) took it apart, cleaned it with part's cleaner (break cleaner, Free-bee from da shop I work at... but I didn't tell you that ) put it back to gether. If that dosen't work groud the conectors (there's 2 back there) to the fire wall. then another thing that top off the fix, I adjusted my Throtle Possition Sensor. make a straight line ( use sharpie. or white out) from the throtle body to the little bracket on the TPS so you can remember where you had it. then with the car off disconect the TPS, spin it left and right till the idle smoothes out. turn the car off reconect the TPS, start the car BAM. well that did it for me, hope that helps.

[ZOOMIGUEL]

change your PCV VALVE as well, it may not be giving enough gas to your engine....

try giving it octane everytime...

[Silvia_Freak]

Also Try TPS sensor...Try adjusting it...I believe its like 8mm

[Black on Gold]

It does sound like a Vac leak. My KA did the same thing until i plugged some up where they go and now the engine hardly moves. I used to be scared i'd jump out of the hood

[fricke21]

my car shakes like a tank, i ve replaced my spark plugs and distributor cap.i dont know what 2 do

[WWJD]

last time I checked tanks dont shake?

[Black on Gold]

Try checking the FPR too.

[fricke21]

ok dude my engine shakes really bad but when i hit the pedal it stops but my car sounds like a gocart

[The Rookie]

lol my fuel rail was loose and not tightened all the way i found out when i turned on the AC the heard a whooshing sound come from the engine bay opened the hood and it was the fuel rail then i pushed on it and my car idled so smooth i almost cried, its fixed now.

[WWJD]

exhaust leak?

[fricke21]

yea i tried that but my fuel rail is on tight. i gotta a magnaflow exaust on my car almost 2 years ago and it also shakes like crazy.could it be my manifold it doesn t backfire?

[adrianfromthecastle]

So over the past month or so my car has been idling funny, when i sit at a light it likes to jump between 500-800 rpm and shake, once i get above 1000 RPM its just fine, it stills pulls hard on the freeway does all the nice little things it usually does, but once i get to a light and the revs get below 1000, it starts to sputter like its gonna stall and i have to give it some throttle, I've already changed the fuel filter to a Z32 one checked all of my fuel injectors and got new spark plugs, whats weird is that it was doing this until about a month ago when i filled up (with what i believe to be) 98 octane at a gas station near the local track, funny thing is i didn't notice what octane it was until i put it in, I've checked for vacuum lines and i cant seem to find any, also i thought that maybe the fuel pump might be going out, could this cause it to have rough idle?

thanks for all of the help in advance.

are you running rich?

[The Rookie]

actually car was fixed once i retightened the fuel rail and it passed emissions about an hour ago so i guess its running fine.