In the morning when Im on my way to work my car starts up fine but once I put it into gear the RPMs drop way down and sometimes stalls out. Ive found the trick is to rev it up pretty high and then drop it into drive- the RPMs go way down, it backfires a couple times but then it moves along. After the car is warm the RPMs go down when I try to start it up again but not nearly as far. What the hell is wrong with my Blazer?

 

What year blazer are we talking about here? When was the last tuneup done on it? It is possible that you need to clean up the TB with some sensor safe carbon cleaner. On the newer vehicles, this is most easily done by removing the TB from the intake.

But yeah, we need some more information before we can help out more...

 

Full tune up including distr cap, belts, hoses, wires, plugs done about a year ago. Its a 95. TB? Im thinking timing belt isnt right.

 

You have a timing chain, but that doesn't mean that it couldn't be worn out and skipped a tooth.

TB == Throttle Body.

 

Wouldnt a dirty throttle body cause rough idling or hesitant acceleration? I guess I dont understand how the RPMs dying out by putting it in first gear would have anything to do with the throttle body. Im not being a smart ***, I just am trying to understand how that would be connected.

 

It's a starting point. Gummed up/diry components should be the first thing to do. Not to mention the fact that it is practically free, easy, and can be completed in under an hour. If it helps, good. If not, well, it's one more thing off your preventative maintenance schedule.

And to be more precise, a gummed up IAC (Idle Air Control) valve in the TB will cause exactly what you describe. The PCM moves the IAC valve to maintain predetermined idle speed. Your truck idles much easier, requiring less air, when in park/neutral than it does in reverse/drive. If the computer cannot adjust the IAC valve, it won't be able to maintain the engines idle speed properly.

And I used that as a starting point because you did not provide the information necessary in the beginning.

 

He mentioned it was a '95. You could also check the vacuum and lines. Do you have to mash the accel. just so that it can turn over?

 

Yes, I saw that. I was commenting on the start of this thread.

 

I have to rev it pretty high just before I put it in gear but not to start it or while its idling. Ill also check the vacuum. I guess a leaking vacuum line wouldnt be doing me any good either.

And like I said, I wasnt trying to be a smart ***. If I just get directions from you guys without actually understanding whats going on then I am going to have to keep coming back and wont be able to figrue out anything on my own. Thanks for explaining though. Ill clean 'er up and get back to you.

 

as swartlkk was implying, it sounds like something is wrong with your intake. clean the tb and the iac and the mass air flow sensor. i had the same problem with one of my cars and it was the mass air flow sensor.