2000 monte carlo 3.8L engine. 140,000 miles,

The problem started about 2 weeks ago... when the engine is running (it doesn't matter if you are in park or driving on the highway, it does it at low and higher rpm's) the rpm seems to drop real quick and then go back to normal.I think thats called a "surge" but I'm not sure. It surges about every 4 minutes.No light, no codes.I have searched and read a lot of posts and forums and have come up with these possible solutions.

mass air flow sensor
crank sensor (was replaced about 2 years ago)
fuel filter ( i dont think its the fuel filter though)
catalytic converter ( i hope this isn't the problem)
or tranny messed up.( i dont think it's the tranny because the problem acts the same if the car is parked in the driveway or doing 65 on the highway.)

What do you guys think? I need the problem fixed as soon as possible the car belongs to my mom and she is using the old van.... help please....

 

Your catylic convertor will give you problems at open throttle, not at idle. That's not it.
Clogged fuel injectors? try running a can of Seafoam fuel system cleaner thru it. Use the gas pedal when you do this tank of gas, as running at idle won't wash out the injectors.
Also, check out the post by J Br Ha SS on the same subject.

http://www.cardomain.com/ride/2319272

 

yah, i would defientely try sea foam, its a cheap try first, the cat convertor should be covered under warrnant possibly still, if not then you can get universal ones fairly cheap.....possibly could be the mass air flow sensor or the throttle position sensor

being the throttle position sensor its possible the seafoam may clean it


just search sea foam threads on here and i wrote how to put it in the car

 

wellI drove it today and not only did it dothe surge thing, but the engine turned off on me while sitting at a red light. I put in neutral and it started right up. drove about half amile and the surge thing started happening again?

thanks for replies guys
anymore? thanks a bunch

 

 

replaced maf sensor in the morning. been driving around town all day and the problem hasnt happened. im happy. thanks for replies... hope this thread can help someone else....

erik

 

do you mean MAP Sensor? I am having the exact same problem right now with my 1995 Z34

 

I had that problem with my old Cadillac. It was the the throttle position sensor.

I don't know how Montes work, just a thought.

 

Still having this problem and no cure yet.

 

Try running SeaFoam and check into the Mass Air Flow sensor.