This problem has been goin on for about 6-7 months or longer. No one has worried about it because it hasn't gotten to the point where it is a big problem. But I was told recently that I should try to go ahead and figure it out. It was throwin a code about the evap cannister. So it was replaced. That didn't fix it. So then the gas cap was replaced. It's not horrible just aggrivating. basically what it does is this. When sitting idle it will sit at 700 rpm. Then drop down to 600. then slowly go down to 500 and start feelin like it's gonna cut off. And it doesn't do it all the time. If ya'll have any ideas they would greatly be appreciated.

 

if it doesnt do it all the time then when does it do it?? whens its first thing in the morning or when the engine is hot or what, when, how?

 

It's the damndest thing. I couldn't tell you. It does it so sporatically. In the morning it does fine. It idles up like it's supposed to. I can take it to work some days and it doesn't do it. But when I go tolunch it will most likely do it but not all the time. Definitely does it if I'm on a hill or incline. But it's so off the wall I haven't worried about it and the only code it's throwin is that evap high sensor and evap low sensor. First it said it was the evap itself. Now just the sensors. So I could replace thoughs. But I just don't think that's what it is.

 

sounds like coils i dunno.

 

And what is this again? Year? Model? Options? A little bit of info goes a long way...

Anyway, I would recommend that you remove and clean the throttle body. It is possible that the IAC passages have gotten gummed up causing an unusually low idle. A vacuum leak in the EVAP system should actually increase the idle if the EVAP purge solenoid is open.

 

1999 4 Door LS Blazer.

And I'll try that. Thanks for the info.