bouncing tach at idle while in gear

[4azdmunky]

Ok so this is new, yesterday my wife calls me to tell me that the car is acting up. When stopped in gear at idle the car starts to shutter like it wants to stall. The tach drops to ~450 and then returns to ~1K. it does this close to every 5 seconds.I checked the VSV, everything appears to working fine. Anyone else see this before?base 05 vibe, Cosmo intake

[4azdmunky]

so it appears it may have been the VSV all along. I repositioned it and now the car runs better. It still has a 'hick up' every once in a while, but not every 5 seconds.

[4azdmunky]

ok so this has not really gotten any better.Anyone have this problem before? The car only stutters when in gear and at idle.

[ColonelPanic]

I dunno, mine doesn't idle smoothly either. The tach stays constant (but lies, it always says 800 RPM.) The ScanGauge shows it bouncing around from anywhere between 550-750 RPM, sometimes fluctuates in 50 RPM increments or so. If it is in neutral, it will idle fine, but in gear, it really doesn't want to have a stable idle. Annoys the heck out of me!

[4azdmunky]

for real, my car actually stumbles every 30-60 seconds. It is starting to drive me crazy.It is like a random misfire.

[Pick]

I've noticed at idle in nuetral mine will sometimes start to idle really low but the tach still reads about 800, but i can feel the car stumbling.

[Atomb]

with my old VW a little fuel injector cleaner when filling the tank helped the same problem......i add a bottle of fuel injector cleaner every 10,000km with the vibe and haven't seen this problem.that doesn't necessarily mean that it's the solution (reminds me of the seseme street when ernie has the banana in his ear to scare away alligators...to which bert says "but there aren't any alligators around" and ernie replies "see! it's working!") (wow, a grown man quoting seseme street!)

[4azdmunky]

Tries that, didnt help.However I think i did finally solve the problem. I had pulled the spark plugs and cleaned them a week prior to the problem. So I replaced the plugs and the problem went away. So I think I screwed one of the plugs up.Lessons Learned:1: The plugs do not need to be regapped.2: Do NOT touch the center electrode of the plug with metal (Not sure why, it says this on the Denso site)3: The plugs are expensive.

[JohnC]

Quote, originally posted by 4azdmunky »Lessons Learned:1: The plugs do not need to be regapped.2: Do NOT touch the center electrode of the plug with metal (Not sure why, it says this on the Denso site)3: The plugs are expensive.Good info...thanks.