Weird idle...And light dimming!! dont know wats going on!

[streetnissan240]

I have already searched and i cant find anything about wat is going on with my idle. The car runs decent and everything. I have Cold air, spark plugs and wires. Well at idle my car goes up and down makeing it sound like i have a big cam or something.. haha It did this before but found out i had a vacuum leak so i checked this time and none nowhere checked over and over. I have no clue why it does this and also my air/fuel ratio gauge usually stays in one place wen im on interstate or stopped but it bounces now like the idle does..

Another Thing my car does is that it like dims all my lights and it pulses. it does this every day and night. I thought it was battery and i replaced it, the alternator is brand new and then i thought it was my speakers but i turned my speakers, stereo and almost everything i got hooked up off and still did it. And it kind of pulses with the bad idle i got when i am stopped. And when i am driving it dont get faster pulseing or nothings!

Please help! I have completely no idea how to fix either of these!!

[USMCgetsome]

i agree with alternator and battery. Have them checked again at autozone. Next would be check for vacuum leaks again. Has to be an issue. Those are known culprits of pulsing. Also, faulty fuel pumps or wiring to it can cause it.

[streetnissan240]

yea i never would have thought it would be my fuel pump, but i havent ever replaced or nor the fuel filter so i might do that. I was thinking it could be my idle control valve. but idk.. i have a spare one on my other engine that im thinking about switching just to see it thats it.

Does any other people have any other ideas?? More ideas the better!

[GO240]

All I have to say is don't go to autozone go to O'Rielly's but yeah my S14 did that its probably your alternator but go ahead and check your fuel pump and a get a new filter (go ahead and swap up to a 300zx wix filter way better than the normal one ) my S13 use to do that when i'd come to a stop but then my motor went boom i swapped in an SR and it went away so i still don't know what was wrong... sorry

[MikEEEx3]

i would check all your grounded wires and see if there no caroded. or you could possably have a short some here that is hard to find

[tero404]

check the ground on the casing to ur alternator/ac generator for the pulsing

check the fuel pressure with a fuel pressure gauge by intergrating into a fuel line sitting on the top part of the intake... i think u should be reading 43 psi