By November 18, 2006 2 Comments Read More →

Chevy Won’t Go Faster Than 40 MPH

I have a question regarding my Chevy Blazer- it only goes -30 to 40 mpg. shifts smooth and RPM at about 3000 is the most it will go- we haven’t changed tran filter and fluid yet- we are going to this weekend annd put some Tran X in it to see if it helps- any other ideas.


You mean it will only go 30-40MPH? If all you can get out of the engine is 3,000 RPM I would suspect a problem with one of the following:

1. Lack of fuel pressure and volume .weak fuel pump, restricted fuel filter

2. Restriction in the exhaust system stopped up catalytic converter or muffler not allowing engine to exhale

3. Ignition timing is way off jumped timing chain distributor is loose and has moved,

4. engine oil pump is restricted or not pumping engine oil and the engine is not getting proper lubrication, sometimes overheating is also a symptom

If the engine RPM will get higher, like in the red line area I would suspect a transmission slipping issue. From the little bit of your email, I don t think you have a transmission issue.

Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • jaeymers

    hello all. this is a very big, and common issue with the blazers. I purchased my 95 blazer from a friend who had all these symptoms, and replaced from the fuel pump up to the computer, coil pack, and a few sensors. where he failed to continue to was under the intake plenum!! there is a 6 legged fuel injection system, (factory legs are like fish tank rubber hose) these were ALL melted and dumping raw fuel down the intake, which in turn clogged the cat, idled rough, wouldn’t go over 25 – 35MPH. this system aftermarket at Autozone is only 291.99. the dealer wants near 500! the one from autozone is now a serviceable item which means if the legs ever break or melt again, you don’t have to replace the whole Unit!

    so, having said this, replace this, soak up all raw fuel in intake, replace intake plenum gasket, and put it back together! Last thing, replace the plugs and you are off and running!!

    A smart thing to do is to clear the computer codes by taking out the ECM fuse in the fuse panel, for 30 seconds, then disconnect battery for up to 2 minutes. replace fuse, and battery, and all done!!

    lot of money wasted by alot of people, but this should be a serious recall from GM as the legs break or melt and could cause serious harm!!

    comments questions, feel free to reach me.


  • Johnny G

    disconect exhaust pipes from motor test drive.

    Catalytic converter or muffler is stopped up thanks to your PCV system