Hey! I'm new here; I never new there was a Monte Carlo forum. I drive a '97 Monte Carlo LS, 3.1L. It has 140,000 miles on it.

I'm have issues accelerating but only on occasions. It seems that after 20 minutes of completely smooth and normal driving, my car decides that it doesn't want to accelerate. I'm pressing pretty far on the gas and my RPM's are jumping back and forth struggling to move my car and give me a pretty rough ride. I've put it neutral to see if it's a transmission issue, but it still does the same thing. Now what's weird is that if I park my car and turn it off for a minute or so, the hesitation issue will be gone. What's going on?

Things of note:

1) Had the transmission rebuilt in January.
2) Brand new O2 sensors as of 1 week.
3) Brand new Catalytic converter as of today (I was hoping this was the cause of the issue).
4) New fuel filter.
5) No current "check engine" light on
6) The engine temp is normal and is not overheating.

There was a "check engine" light on for the cat code, but that's now gone but the hesitation is not. (By the way, the shop wanted $32 to reset my freaking code!! What the hell?! I went to auto zone and got it done for free.) I should also not that I had a fuel pump replaced about 2 years ago, and ever since then it's always made a "growling" and "grumbling" noise, but it's always worked fine. A local shop doesn't know what's wrong other than guessing that the fuel pump needs to be replaced. Any body have any ideas??!

 

It is possilbe that the fuel pump is on its way of going, I can't believe that the new cat did not fix the problem. When it is just idling, does the tach. jump around? If it does, give it a tune up with new wires and plugs. Also, it could be an ignition coil or throttle positioning sensor, but the light would def. be on and a code would show for it... When was the last time it had a tune up?

 

plugs, wires, coils(check these) also the filters(air and fuel) basic tune up stuff...if you haven't done this stuff already its definetely time to do this...almost over due...well actually it is way overdue..

then if this doesn't solve the problem it could be the throttle position sensor if the tac is jumping all over...also check the coolant temp sensor(sounds wierd..but this causes all sorts of wierd problems)

also ..its the 3.1 l engine and they are known as much as the 3.4 litre for having bad intake gaskets from gm...have this checked out...make sure if you change this that you go with the felpro kit with the metal inserts in it...i will post the part # on monday when i get back to work

 

It sounds like a fuel pump to me. If it was a misfire from a plug, coil or wire, the check engine light would come on and probably flash.

 

IF you have a fuel pressure tester that would help out.
When was the last time the fuel filter was replaced?
Also fuel regulator could be acting up

Pressure test would be able to check all the about items

 

Well today I brought it in for a diagnostic test, specifically to test my fuel pump/system. Everything is working perfectly. All of my plugs and wires and general maintenance stuff was double check and they all checked out too. They ended up telling me that it's the Transmission which I had totally rebuilt in mid-January. What makes me a little hesitant is that when I'm stuttering but driving and I pop it into neutral and hit the gas, my RPMs do jump way up but can still fight me a little. It's not nearly as much, but it's still fighting it. If I stop and put it in neutral and hit the gas, there isn't any hesitation. It is still under warranty, but my biggest problem is that I had my transmission rebuilt in Dallas and I am now in Austin, about 220 miles away. I don't think I can make it up there and they don't have any other locations. I might have to higher a tow.

What I did notice is that when I was in gear and stopped to rev the engine, I put my head out my door and it almost sounds like my muffler is making near backfire noise. Could some material from the cat have clogged the muffler? If so, why would this only give me an issue after 15 minutes of driving? [sm=smiley18.gif]

 

If the cat is coming apart, yes a piece can get clogged in the exhaust system. If its a big enough piece it will not be able to go around any bends in the the exhaust.
I worked on a Saturn one time and this was the cause of the car not running. It would start up after a few minutes it would shut down.
We took the o2 sensor out and ran it.
The broken pieces were found in the exhaust pipe just as it made a bend to the right.

 

just an update.

it wasn't my transmission, and what it was i can't tell you. i brought it to a different mechanic and he worked on if for 4 days and couldn't figure out the power loss and acceleration issues. he called me on the 4th day and told me to pick up my car and take it to a dealer to figure it out. i picked up my car and he was very cool about it and didn't charge me for trying to fix it. he even said that it was working fine for the moment, which i replied "yeah it does that". well long story short, somehow he did fix it! he did not change a single thing, he just looked for the problem. perhaps something just wasn't connected or need adjustment? i don't know...it's weird. i've had my car for a week now and it's working perfectly after not working perfectly for 3 weeks. either way, i'm a happy customer.

 

Welcome to the forum Matt!!!

4 days and didn't charge you!! Thats incredible!! I'd still tip the guy at least $50 if you are part time side of labor and $100 if employed full time. That is completely nutz not charging you for anything... imagine working on your job for 4 days and your employer not paying you. I'd give a little sumthin' sumthin' just in the name of karma... you don't want that to come back to you and you might feel good giving him something for his trouble.