Ok, guys I've searched and searched and don't know what else to do. My car is jumping. Yea, I said jumping. When the car is in drive and my foot is on the brake or the emergency brake is on. You can feel the car jumping and the RPM's keep falling (only slightly). And today when I was driving and having a real bad case. I speed up to about 65 and the car just shut off in the middle of the road. I pulled over and cranked it and it started right up with out hesitation. What's going on. I've seen others that say the replace thier ignition coils and sometimes this fixed their hesitation. Does this sound like ingnition coils? What do they actually do? I never have a problem starting the car or any thing else. But it just hesitates and jumps(sometimes). Also when driving sometimes the car is fine, but I will just be driving along and the RPM's will rev up like I'm stomping on the gas. So then the car will try to down shift. Man I need help. Any suggestions will help.

 

When the car revs up on it's own while you're driving, does the car also feel like the engine is no longer powering the wheels? In other words..., does the car loose speed - even for a second?

 

No, I tries to take off. Usually I'll just be driving at a low speed around 2000 rpms and then all of a sudden it feels like I punched it. But only for a moment then it realizes I didn't floor it a slows back down. I checked my ECU and it still gives me 0304 code which is the knowck sensor, but it wouldn't affect mt performance like this would it? I was thinking it would throw a code for the throttle position sensor. Could this still be the problem or part of it???

 

Ummm...., what are the odds your cruise control button is set to 'on'?
If your cruise is 'on' and is malfunctioning, then that could cause this.
Otherwise, I'd be thinking bad sensors, or dirty connections to those sensors.
Sorry I couldn't be more helpful tho.

 

NO, I'm pretty positive its not the cruse control. I never use it.

 

I had a similar problem with an RX7 and I think I narrowed it down to the emissions system and or the TPS. It was like it was changing the air fuel mix from lean to rich back and forth making it jump. Check cables to throttle, clean MAF, Clean Throttlebody, Check 02 sensor, check knock sensor, I also had folks tell me to check a coolant temp switch on my RX7 as it also had something to do with emissions. YOu could check vacumn lines, also leaks between MAF and throttle body, or any other kind of intake leak. Folks have also cleaned origninal grounds and added new grounds and have had some success on other cars. Some posts here have described unplugging the 02 sensor and driving around to see if thats the problem, when unplugged the ECU goes into a default mode. Anyway, others may have a better idea and may know more of what they are talking about. I just thought Id give you a few ideas on what you could try that might not cost much, hopefully it will turn out to be something simple. Good luck.

 

Success!!!!!

I pulled the Throttle position sensor and blew in it and pluged it back in. The Car runs like a totally different machine. Thanks DaBox for the tip.