Running lean?

**MrTube** · 05-04-2012

I have an 06 base model with 51K on it. For a while now if I shut the car off and start it a minute later it will shake a little as if its running lean but then it clears up, maybe this is normal?

This morning the wife and I drove our normal 50 mile commute and pulled into a place to get some food. After a few minutes we started the car and went on our way. I noticed when taking off the car shudders as if its missing. Again to me this feels like its running lean rather than a spark issue. I'm at work and the wife is driving to her job and said its still doing it.

No SES light lit, at least not yet. Is this something I should be concerned with? Perhaps a MAF problem?

Its around 55F and very humid out right now.

**cerick08GP** · 05-04-2012

well ya it could be the MAF, but I would start by cleaning the throttle body. If you don't clean the TB they can/do get gummed up and cause idling issues.

**MrTube** · 05-04-2012

Will do this weekend.
However just so there is no confusion, when taking off it was shuddering at around 20-30MPH while accelerating to 40-50mph so defiantly not idling. I'm assuming a dirty throttlebody could also effect it during this as well? Nice steady acceleration, nothing hard.

**cerick08GP** · 05-04-2012

Well that info helps a bit.

Now I would go more with a tranny problem, or a wheel issue. That said, IMHO ppl should clean the TB about every two years because that is all it takes to never have any issue with it.

Trannys I’m not knowledgeable with, but it I would put it high on the suspect list. The wheels should be easy to check. Does the low end shuddering repeat at a higher speed? I’ve had wheel issues before and when they hit resonances they will shake in narrow mph ranges. And other mphs the car rides pretty smooth.

**MrTube** · 05-04-2012

Thank you for your reply.

I don't know if it does it at higher speeds as she drove away without me. I will do some testing tonight on the way home.

I doubt its tranny or wheel related as when she pulled away I heard it in the exhaust. Perhaps studdering is a poor choice of word, but I don't know what to use. Perhaps missing is the best word in this case. I'll clean the TB this weekend and give everything a good visual inspection.

**SlowNA06** · 05-04-2012

Clean the throttlebody with throttlebody cleaner
Clean the MAF with MAF cleaner.
Check the intake air filter for blockage (bout time to replace, anyway, if you haven't yet).
Check for disconnected or loose vacuum lines.
Hook it up to a scanner and see what codes are thrown.

**MrTube** · 05-05-2012

Well on the drive home last night the car ran normal again. No missing or spuddering of any kind whether partial throttle or WOT. I'd like to think it was just a fluke, but that doesn't seem to happen on newer cars?

I'm going to clean the MAF and throttlebody regardless. Also changing the thermostat as I suspect it sticks a little from time to time.