My 1999 altima has a shakey idle when i have it in drive and turn the signal light on. It only does this with either signal light on and i can turn on everything else like the a/c, radio, lights, highbeams, and dome light on in it will stop doing it when the turn signal is on. I had the alternator checked and it passed so its not the alternator. the battery is only 4-8 months old also.. Could it be somethings with the grounds in the car??? And also the idle only shakes from 600-700 when this is happening. Thanks Matt

If the alternator passed inspection then it possibly could be a bad ground or other wiring issue. I would trace through your wiring harness and check for corrosion, loose connections, e.t.c. and then go from there.

Okay, Thanks I will run through and check the wires tommorow. i was reading somewhere else that it might be an IAC or IAVC Problem or malfunction? Could it be also be an leak in a vaccum line anywhere? The car has 236,000 miles so im thinking the motor could be calling for attention. thanks for the quick reply!

Your welcome sir! The IACV could be the culprit but what makes it sound wiring-ish to me is that it only does it with the turn signal on. Wiring problems make cars do funny things...

Thanks, Thats what i hope it is, ill dig into the car tomorow and check it out. But lately at just a regular idle in park or nuetral that cars idle has had some slight backfire, but nothing to make the rpms drop down or rev up. Could it maybe be the headers allowing alot of air flow and the motor is trying to set a low idle at the same time compensating for the load of the alternator?

By the way nice car!! I really loved the 240's but got to loving the altimas since not many mods have been done to them that i know of.

So i cleaned all of the grounds and blbs and there was no corrosion or anything on any of them. Is there any hidden or trickey spots where i should look for any more grounds?

recently just got a 1993 240sx hatch back for 150$ its just the shell no engine or dash. Was wondering if an s14 SR20DET would fit in it. Or should i stick with the original s13 90-93 SR20DET, is there a difference between the the two engines?
i know that the 98 s14 SR20DET has 220hp. 20+ hp than the other SR
thanks