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

[blacksambo]

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