Idle Stumbling

[articzap]

Well I can't figure it out. Car runs perfect except for at idle. Sometime it idle at 950 RPMs and be fine. Other times the idle will surge and dip down to almost 550 RPMs then shoot up to 1000 RPMs then drop back down. Vacuum when at the 950 RPMs is -19inHg. I can't figure out what would be causing the random crappy idle. I think it might be because I'm running rich? I'm completely guessing. Other this problem the car runs perfect. Any ideas?

[Rin5]

only thing i can think of is vac leak...

i had this problem when i didnt know my brake booster was leaking (forgot the check valve)

at first it was ok i just hit the brakes no prob...then soon when id come to a stop it started idling funny and sometimes turns off...then eventually when i was running 55-60mph and stepped on brakes slowly as usual...then i heard PHOOOSHHHH and my brakes were completely out...i alleviated my problem by finding the check valve and putting it backwards to block off air...the brakebooster was still done but atleast i could use man powered hydraulics..lol...but i replaced the booster last month and everything is back to fine....

look for holes leaking air...

as far as running rich...what do you have?

FPR, up'd injects or rail?

cuz if its completely stock fuel then you shouldnt be running rich

i have 255walbro and 300zxTT fuel filter and my stuff doesnt go rich...only time it went rich was when an intercooler coupler blew off a lil (wasnt tight enough) and it had like a 1/4 inch gap to breathe from...

[articzap]

Walbro 255 lph with Synapse FPR. Stock injectors. I'll have to check my master cylinder and check valve but that should be good.

This has me stumped and I just want it fixed!

[ca18detgabby]

maybe your tb isnt closing properly?

[r34 gtr]

You know, my car did that back in the day, and adding some big grounding straps fixed it for me. I'm not saying it will work for you, but it can't hurt and it won't run you more than $20 to try. 4ga battery ground cables from Advance auto parts with an eye on both ends. I run two to the head (one on each side) and one to the block.

Check for vacuum leaks too. I had a couple and it caused my idle to be very high, but not to go up and down like that.

Gabby, that link to Defi gauges for sale in your sig just takes you to the electronics for sale forum. Just so you know.

[ca18detgabby]

LOL i forgot to take that link off..... I already sold them

[r34 gtr]

There ya go!