Every once in awhile I will be driving my car and it will misfire and the check engine light will come on.

Every time I am driving I hear a rattling sound when I hit a pot hole or on a uneven road.

When I apply the brakes to stop my car, it wants to almost shutoff.

diagnostic and repair 470 CPC 76554 diagnostic trace to BCM dropping signal traced wires cleaned connections n ran new ground wire went for test drive tcm failed again told it was replaced due to short when it touch battery really hmm my battery is in trunk of car not under hood
now my air is working strangely is ther a connection of some sort
i really need honesty i don't feel safe in my car. i

I have a manual transmission and the gears are getting locked when I drive on streets where I have to make constant stops. Clutch and master cylinder and gear panel have all been changed already, but problem keeps happening. What is causing my gears to get stuck?

This car of my girlfriends has apparently be stuttering on acceleration for quite some time and I just found out after needing to drive it a few days. The car hesitates to downshift at any speed, hesitates to take off and gets 18 mpg city at an avg of 20mph. I took it to the Dealer to see if they could clean the fuel system after replacing spark plugs that were completely white even though they were only in there 40k miles or so and cleaned the throttle body(a notorious cobalt problem) by taking it off and doing my best to wipe it down with a rag and throttle body cleaner. The GM Top Engine Cleaner they used worked great for one tank of gas which also had seafoam in it, then upon the next fill up the very consistent and annoying misfires and hesitation under 2k rpms reappeared. Over 2k the hesitation is much less than what it was but still there sometimes. Im hesitant to take it back to the Dealer so I called Firestone. They said the complete cleaning will cost 140 dollars and I need to leave it there all day so they can really evaluate it. Could someone please tell me some specifics about their service to bring up if I decide to make that appointment and have it "fully cleaned" according to them and is it likely the carbon build up or something more? Any answers or advice are appreciated.

Also, on another note is Firestones gas tank fuel system cleaner better than say lucas oils or techron?

Thanks very much

My car started losing power intermittently so I had the fuel pump changed. The problem still persists and now my car doesn't start up right away. It usually takes 2 turns of the ignition to start up.

I just bought an '06 Chevy Cobalt. And it has been doing really good when the engine is still cold. But after driving for awhile and the car gets hot it starts dying on me. When I stop and idle. And even when I go to slow down. When it dies I put it in park and turn it off. It fires right back up and dies again before I can even get it in drive. I need help! The guy I bought it from is a mechanic and he has been looking for the problem for almost a week and it still isn't fixed. Any suggestions would be greatly appreciated...

When I raise the hood up I can hear but I never cut off it just keep running and in the car waste a lot of gas

All lights and radio come on battery is good can you please help

If im going down interstate at 65 or 70 and let off the gas pedal it will slow to like 55 in no time