Idle surge

**Lqdsilver** · 02-12-2010, 08:21 PM

Started her up the other day, after sitting for a few mins it died. Now throwing a code, not sure which yet. 5ft of snow this week haven't made it to get scanned somewhere.

Before occasionally in drive it would surge from 3-500rpm. Thought it was just the tsp mail order tune, wouldn't do it a lot. Now it's almost all the time in drive, at lights and such. Just curious what it could be before I can get it scanned, and the cause of it.
A4 3600stall tsp mail tune, full bolt ons

I plan on changing to 3.73s and a full frost dyno tune in the spring, not sure if I should wait it out, or if that would fix it

**Cutlass** · 02-13-2010, 03:58 AM

could be a vacuum leak. Maybe low fuel pressure (ie bad pump or restricted fuel filter). Could be a lot of things. Let us know what code is stored in the computer.

**pajeff02** · 02-13-2010, 05:08 AM

Dirty throttle body or idle air control valve? As mentioned, check the code(s) and start there.

**0rion** · 02-13-2010, 05:13 AM

where is your idle at normally? I had to bump mine a few rpm after the stall because the car would surge and want to die.

**DaddySS** · 02-14-2010, 06:57 AM

Most of the idle surges that aren't tune related are soved by cleaning the MAF, fixing vacuum leaks or replacing o2 sensors. Let us know what code you have and in the meantime, clean the maf and check for vacuum leaks.

**Smittro** · 02-14-2010, 08:34 AM

Clean the IAC sensor opening... It's the little silver or black cylindrical looking sensor that is located on the TB. Usually held in with two scews.. Get an old tooth brush or a mini wire brush with nylon bristles. Do NOT use a small metal brush as this will damage the pintle seat. Use a spray cleaner and shoot some into the hole then use your brush inside the hole Look inside between sprays and scrubs to be sure your cleaning the seat for the pintle valve.. This area likes to build up with carbon and can sometimes cause a distortion in air flow. Your IAC could be cycling in and out trying to overcome the reduced flow.. Hope that helped and good luck..

Note: Do NOT pull or twist or otherwise manipulate the pintle, (plunger type valve in your IAC) this could serve to ruin it just wipe it off.. DON't spray cleaner into/onto it .. Though the sensor is'nt expensive you can't drive the vehicle without it and a damaged/worn/dirty IAC can create driveability issues..

**Lqdsilver** · 02-19-2010, 12:05 PM

#6 plug is arcing to the block. Seems to be the likely source, gonna change wires, check plug, hopefully she'll be roaring again. Not sure of code it was throwing, lazy to go to autozone and the old ass scanner I have access to won't read it.
Keep y'all posted

**Lqdsilver** · 03-05-2010, 06:35 PM

Well new wire fixed the surge.
The SES light was a blown MAF fuse.
Hopefully no more problems for awhile

**pajeff02** · 03-05-2010, 06:39 PM

Good to hear that the problem is solved. Strange that you had two completely different things go at the same time.

**Lqdsilver** · 03-05-2010, 07:12 PM

Yeah... Bit weird, hopefully it's not going to be a recurring problem.

**Lqdsilver** · 03-10-2010, 08:28 PM

.... CEL is back on, and my old friend surge is back too..
Can't look at it till morning, but guess I'll work till autozone opens and get scanned again.

Feel free to post up some worst case scenarios for me.

**pajeff02** · 03-11-2010, 06:20 AM

Did you check the MAF circuit/fuse?

**Lqdsilver** · 03-11-2010, 11:37 AM

20amp ENG SEN blown

**pajeff02** · 03-11-2010, 12:33 PM

Originally Posted by Lqdsilver

20amp ENG SEN blown

Start looking your wire harness over to see if you have any wear marks or areas that the insualtion may be scrubbed off. Also, pull you MAF connector apart and look at the pins to ensure that they are not bent. Have you had anything else electrical apart recently? If so, go back over your connections and routing.

**Lqdsilver** · 03-11-2010, 05:40 PM

Is that fuse just for the maf? Gonna look at it tomorrow but I changed fuses and it blew again and stalled out in about 2mins

**Cutlass** · 03-11-2010, 06:47 PM

Originally Posted by Lqdsilver

Is that fuse just for the maf? Gonna look at it tomorrow but I changed fuses and it blew again and stalled out in about 2mins

No, it powers up the heater circuits in all 4 O2 sensors, MAF, and the Stop lamp TCC switch.
I'd say check your O2 sensor wiring for shorts to the hot exhaust headers/pipes.

**Lqdsilver** · 03-14-2010, 03:25 PM

I have the back two tuned out. Haven't gotten a chance to check the fronts, feels like monsoon season here.

I did however let it reach 200degrees, put a new fuse in and it's holding so far, so if it's blowing at startup temps could that narrow it down?