99 Astro bucking slightly at slow speed until warmed up.

[subsailor592]

99 Astro 143k. Good shape. From a cold start to the first 15 mph transmission feels non-responcive causing a mild bucking. After the van is warmed up the symptom goes away but not entirely - you can still feel it slightly up around 50 - 60 and in lower speeds unlike when it was cold seems almost normal again. Check engine light went on so I brought it in for a code check / can't remember the number, but there is a part in the air filter that houses a sensor. I was told there was some kind of misfire going on caused by incorrect combustion mix i.e. to much, not enough air or fuel. Can this part assuming its bad cause "misfire?" It looks like a thick coaster you'd put your drink on. Could this cause bucking? Sure would be better than transmission issues. Thanks.

[astro44]

I have a '98 and it does the same thing but mine is only from cold start at higher speed. It certainly feels like it is starving from something, gas or air, and this would lead me to believe it's a censor? I'm no mechanic so this is all I've got, I'll be watching this post in hopes sonmeone will offer more information. Good luck.

[CD Smalley]

Sounds like a carbon buildup on the back of throttle blade(s) to me guys.

[astro44]

Are the throttle blades inside the throttle body? Can this be cleaned with throttle body cleaner by spraying inside throttle body? Hopefully I'm on track with my assumptions? Thanks.

[CD Smalley]

You are on track. I think this could also be an EGR valve issue as well.