3rd Jun 2010, 03:21

My car is over 200,000, and I've had zero problems except the service light being on, and the gear shift light and clock light off (which apparently you have to take out the dash, so I said forget it).

That being said, one time last year in the winter I turned it on, and it was revving like crazy. RPM at 3/4 when idling. My boyfriend at the time insisted it would go away once I put it into gear. So I put it in reverse, and the moment I released the brake it was as if I had floored it. I almost rammed into a car. So I put it in park and said I was not moving it, it smelled like burning and still revving sooo high. He finally got out and checked under the hood.

While he was doing that, I was looking around inside to see if something got bumped or pressed. I pressed the traction button and immediately it went back to normal. Nothing else since besides some rust..

30th May 2012, 20:33

Hi. I too am having the same problems.

Although it sounds like most peoples are automatics, mine is a 5 speed 2 door 2000 Sunfire with a 2.4L engine.

In the last month, all of a sudden the car started acting up. Wants to die sometimes when the gas pedal is depressed erratically or when turning. Sometimes just idling and then it dies. Driving down the highway, it chugged, and you can feel the "lag" when you press the gas pedal to accelerate, and then it surges to life again.

Starting off was extremely difficult due to chugging, no power, misfiring and coughing out the throttle body. Only under about 2500 RPM it does all of this. Over that it runs decent. My fuel mileage seems OK. Only happens when it's warm also.

Today it started to over heat on me, and I heard the fan running. Smells hot and "Noxy" out the tail pipe. I got home, checked the coolant and it was fine. So I decided to start pulling plugs to see what makes a difference, with everything plugged in, and I can use the throttle wheel on the throttle body to rev the engine. When I did this, it chugged, bogged and barely wanted to rev for 5 seconds. Then it surges to life again. Seemed like it was starving for fuel...

Now here's the odd part. I came to the MAP sensor (the one with the vacuum line going to it by the throttle body), unplugged it... the engine had a small burp on revs, and then settled. I revved it, only to find it very responsive. So I drove it down the road and it drove perfect. Nothing wrong with it. Responsive and healthy again. Now I always thought if your MAP sensor wasn't working (which mine isn't because I unplugged it) that your engine would run crappy? I believe the fuel mileage will probably get worse. But I masked the problem for now, so I can at least drive it until I figure this out.

My question is to someone with more experience and expertise... What am I masking or compensating for? I'm thinking fuel. But so many people have this problem, there has got to be a way we can figure this out, if I can unplug something and have good results. What does it need to run like it did with it plugged in again?! Any help would be greatly appreciated. Thanks!