Brake booster? And yeah, I searched :)

[ianae86]

Alright so the problem seems to be a common one but I've never found a solution that has worked. When I first start driving my car I experience no idol problems whatsover. However, once its been running for a while, everytime I come to stop in neutral/clutch in my idols drop from the smooth 700-750 to 500. Never any lower and it always bounces back up. I inspected the lines that run from the booster to the engine and even blew through the valve on the firewall where the lines meet to make sure it wasn't clogged. The problem persists. I've sprayed WD-40 around the lines with the car running and noticed no idle changes. Could it be the booster itself? Please help me out. Its not stalling but the rough idling when stopping is getting old quick. Thanks in advance

[Dattebayo]

Is the car's idle only when braking, or have you tried while in motion letting the gas off and letting it go down to idle without using the brakes? If your idle is rough then it would be your throttle body needs a cleaning because the area around throttle plate is gunked up...

[ianae86]

Is the car's idle only when braking, or have you tried while in motion letting the gas off and letting it go down to idle without using the brakes? If your idle is rough then it would be your throttle body needs a cleaning because the area around throttle plate is gunked up...

Nah, just when braking. I've done a full tune up (plugs/wires/cap/rotor/air filter/cleaned throttle body/cleaned MAF/fuel injector cleaner in the gas)and it idles like butter when I'm stationary. Its almost like it holds a vacuum for like 2minutes because the first couple times I brake its fine as well. Just after a few high speed stops its drops down. Thanks for getting the ball rolling though!

[ianae86]

Bedtime bump!

[Repo Man]

Ian, that's a tough one. I've never heard of that before, so I moved your thread to Nissan Online Mechanic. Hopefully we can get this figured out for you.

[ianae86]

Thanks so much for the move! Didn't even realize that was a section, haha.

[ianae86]

I should maybe mention a couple other things. When I bought the car, the coolant reservoir tank was damaged and I assume as a result instead of fixing it the previous owner just took out the thermostat (derrrrr) so the car runs rich most of the time as it never FULLY warms up. Don't know if this would have anything to do with it but I doubt it since its only when i brake. Help?

[vancouverbc]

You dont have problems when the car is cold because the air regulator bumps up the idle. The most common solution to your problem is cleaning the IACV unit. Look up IACV in tutorial link in my signature.

[ianae86]

You dont have problems when the car is cold because the air regulator bumps up the idle. The most common solution to your problem is cleaning the IACV unit. Look up IACV in tutorial link in my signature.

Thanks for the suggestion. Would something like a dirty IACV cause an idle drop only when braking though?

[vancouverbc]

definitely

[ianae86]

definitely

Thanks man! I'll definitely try and get it cleaned. Looks like a pain in the arse to remove though. Oh well, i'll go eyeball it when I get home tonight. Thanks for the tip