Erratic Idle.

[blacksambo]

Hi,

Our black '99 shows a 171 code and erractic idle, especially when in neutral. It likes to bob up and down after reving. Any thoughts? Thx

[Mrcln1]

I had a similar problem and it was my lower intake gasket. You spray starter fluid around the gasket and it rev's when you get to the leak. If theres a leak and it's under the intake where you can't reach with starter fluid it'll be harder to tell. Hope this helps. Good luck!

Mrcln1

[VehiGAZ]

Same suggestion - probably the intake manifold gaskets.

What was the story with these? I recall discussion that a TSB was issued to lower the torque specs for tightening the manifold bolts due to stress on the gaskets. Anyone recall this? What were the corrected specs?

[WormGod]

Same suggestion - probably the intake manifold gaskets.

What was the story with these? I recall discussion that a TSB was issued to lower the torque specs for tightening the manifold bolts due to stress on the gaskets. Anyone recall this? What were the corrected specs?

Really? First I heard about this, but it would make sense, considering I have been through 2 sets of gaskets in 2 years time because of the !@#$ing 171. I was ready to just mig weld a beautiful bead around the plenum and seal it up for good, heh.

[taylorRichie]

After replacing my IAC, and PCV, then cleaning both MAF, and EGR, it ended up being my intake manifold gasket :D

[blacksambo]

Thank you for the input. I'll change the plenum gasket and watch the bolt torque.

[WILLY]

I think the original torque spec was 18 and dropped to 13 cause of all the gasket failures.I changed both upper and lower and torqued to 13 and have had no probs.yet

[crotchrocket]

i must say i have had an issue twice recently where i have pulled to a stop at a junction in drive and the revs have climbed and its tried to power forward into the road!!!!

My 300zx had an Idle controll valve that i cleaned up to sort the idlle out......what does the vx have??

[taylorRichie]

It has an Idle Air Control Valve... Right above the Intake hose. I cleaned mine first... didn't fix the problem, so I replaced it... didn't fix the problem :D

HA...

Those $3,000 Scantool deals the dealership has can come in handy... wished I had paid the $50 diagnostic fee before pouring good money after bad...

[etlsport]

erratic idle has been caused by a few different things in the VX

fuel pressure regulator (usually most noticeable on startup though)
idle air control valve.. dirty/clogged
egr valve.. dirty/clogged
intake gaskets.. cracked/leaking

[WormGod]

Talk about luck. After replacing my manifold gaskets my 171 went away. For good I thought. Been gone for a couple months. Started her up yesterday (warm start.... she was running about 30mins previous) and she bogged before wanting to cut out. Gave it some revs to keep it running and BLING.... CEL, 171.

I give up. Explosives might be in order now. The old dog is about to get taken "out back" out of frustration.

[gumby]

Did you use oem gaskets? I just replaced my own after having the dealership replace them for me three times. When I got in there I saw the original gaskets were made of plastic! What crap....

I replaced them with Rock brand gaskets and all is well now. I don't know which brand you used, but I'd like to know.

I'm a bit shocked to know that's the material the oems were made out of.

no wonder they cracked to pieces in a matter of about 1 year...

I have considered making new sets out of solid teflon if I have any more problems.

[blacksambo]

Well, I replaced my common chamber gasket with oem and still get the light. But what's interesting is that it only idles rough in neutral. In gear it's fine. Any thoughts? Thx

[Ldub]

Did you use oem gaskets? I just replaced my own after having the dealership replace them for me three times. When I got in there I saw the original gaskets were made of plastic! What crap....

I replaced them with Rock brand gaskets and all is well now. I don't know which brand you used, but I'd like to know.

I'm a bit shocked to know that's the material the oems were made out of.

no wonder they cracked to pieces in a matter of about 1 year...

I have considered making new sets out of solid teflon if I have any more problems.

Would it be possible for you to post a link, or more info on these gaskets?

I'm familiar with Rockauto.com, is that where you bought them?

Thanks, L W

[WormGod]

I used OEM on every re-seat. Like I said in another thread, I am ready to whip the welder out and run a bead around the entire thing, heh. Dead tired of this !@#$ now. This last time I torqued at 13lbs and still.... this. :mad:

[blacksambo]

If the gasket is leaking and you spray it with carb cleaner the idle should go up slightly. If it doesn't it may not be the gasket, at all???