I own a 1996 chevy monte carlo 3.1. I have had this problem for quite a while now and it just seems to be that i'm chasing a ghost. The engine stumbles upon startup and and the RPM's jump erratically between 800-1100 RPM's. When I go to move the car (ex. Reverse, drive, overdrive) the engine stumbles and sounds and seems like it's going to stall out all together. If I manage to get it up to speed, it runs great. If I don't it tends to stall out and not start back up until I let it sit for a few hours. I know i'm moving in the right direction but this car is nickel and dimeing me with all the parts i'm buying for it. So far I have replaced the IAC valve, throttle position sensor, spark plugs and cables, and the ignition module. I will soon be replacing the coil packs but I want to know beforehand whether I should spend the money on them. Any insight from anyone who can give me a clear answer on this problem? Any thoughts and help will be greatly appreciated.
Don't replace anything else until we are sure. As far as the problem, if the check engine light hasn't come on, chances are it isn't an electrical issue. Check to make sure the fuel pressure is within spec, the regulator is working, and check for vacuum leaks to start. Keep in mind, it has a lot of miles and it could be many things causing the issue. If fuel pressure is good, you have good spark, there are no vacuum leaks, then check engine compression. Also, have you ever cleaned the fuel injectors?
August, 31, 2011 AT 8:23 PM
Thank you for the reply. I have never cleaned the fuel injectors. I honestly don't know how or how to even get to them. I'm not a mechanic so not really sure. I'll definitely look into it and see what I can do. I was also told today to check the fuel filter as well.
September, 1, 2011 AT 1:16 AM
The fuel filter can cause a problem, check fuel pump pressure to see if it is steady and within spec. If you go to our home page under the DIY section, you will find a video and directions for doing it.
As far as the injectors, go to a parts store and ask them to help you find a quality injector cleaner. Most of them are just added to the fuel in the gas tank.
Let me know how you make out with this.
September, 1, 2011 AT 3:49 AM
Ok will do. Thank you for the help and i'll let you know how I make out.
September, 13, 2011 AT 6:31 PM
I have a 1998 Monte Carlo 3100 that has been stuttering lately & recently stalled out while I was reducing speed right in middle of road. I could not get it restarted so I had it towed home. Due to unforeseen circumstances, I had to replace my radiator & I also changed fuel filter. I can get it running if I hold down gas pedal, but then it stalls out on me. I checked 1 of the spark plugs & it seems to have a very, very large gap. I am not a mechanic & I have no one to help me w/ all of this. My husband left over a year ago & my daughters car is broken also & I have been trying to fix hers since May.
September, 13, 2011 AT 8:05 PM
Well, I did find out the problem to my car and it turned out to be the fuel pump. If a spark plug has a large gap replace all of them and the cables. Since you already replaced the fuel filter, replace the fuel pump and strainer. That's just what I came up with for my car. I don't know your entire situation, but my suggestion is have the fuel pump replaced.
September, 15, 2011 AT 12:32 AM
Thank u. I will get the spark plugs this week & hopefully I can afford the cables. I ll probably have to wait for the fuel pump until I have more money. I will see if it works. Again, thank u.
September, 26, 2011 AT 1:04 PM
In response to Inkd4life. Has anyone mentioned checking the EGR valve? If you keep your foot on the gas (i.E. Accelerating or just revving it slightly at a stop), does the stalling still occur? I have automotive training, but i'm not an active technician. Any experts have an opinion on the EGR valve?
September, 26, 2011 AT 3:08 PM
Since it is fuel injected engine it will result in high rpm during cold start.I will suggest simply to clean up the air filter and fuel injectors and check for pressure valve in the fuel line. And always wait for engine to warm up own its own and then accelerate to ride further.