What could be wrong with my car? Rough idle, misfiring, hesitation. Help please?

I would buy a bottle of Seafoam and put it in your gas tank. If that doesn't work, then I would change the fuel filter, which you can do without a mechanic.

Engine Misfires At Idle

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What could be wrong with my car? Rough idle, misfiring, hesitation. Help please?

I have a 96 Sunfire and lately it's been having a hard time turning over right away. It depends on the day, but sometimes I have to try to start it 5 or 6 times before it turns over.

After I get it started, sometimes it idles a little rough... the engine is making what I could best describe...

It could be a sensor. Does it run okay AFTER it gets warmed up? The coolant sensor is what makes the car run when it is cold outside, it tells the computer to shut off other sensors and then to add more gas, to keep the engine running. The engine needs more gas when it is cold, because the gas is not vaporizing well, and so it doesn't burn as good as hot gasoline. So until the engine warms up, the computer puts in more gas, just to keep it running. That was what "chokes" did on cars with carburetors. The choke on carburetors, closes and makes the engine run "richer" (more gas) until the engine warms up.

Once the engine gets hot, the coolant sensor then tells the computer to go back to normal run, and it will then open the other sensors, and the car runs okay.

But if the coolant sensor is bad, the car will run "rich" all the time. And maybe run rough. This is so that a engine does not run "lean" (not enough gas) and burn up the pistons. So when the sensor fails, the computer runs "rich" to keep the engine from damaging.

The Oxygen sensor is another one that can make a car run bad, it senses the oxygen in the fuel and adds or substracts fuel depending on how rich or lean the mixture is, and it tries to keep the mixture at 14.7 air to fuel ratio. If this goes out, it will cause the engine to also run "rich", for the same reason as the coolant sensor...to prevent damage.

Other sensors also affect the running of the engine.....so you need to have these checked, by a shop. And, being as your car is 15 years old, be sure to check the spark plugs, for in a 4 cylinder car, one plug can make the engine run real rough.

There is NO quick fix...you need to check ALL things that can cause the problem.

I think that if it runs okay when hot, then it has to be the coolant sensor. It would run bad all day long if it was something like plugs, or one of the other sensors.

Jessica, You've been at this for a couple of weeks now. Guessing and surrounding the problem with parts and money has not worked. You will not get a competent answer on the internet. Someone needs to actually run some diagnostic tests on the car to isolate the problem. Trust me spending the cash for a proper repair will actually be cheaper in the long run. I guarantee it. If you must solve this puzzle on your own assemble some basic mechanics tools and consult a manual. you will not fix this on yahoo. You just won't.

try replacing the fuel and air filters, if it is fuel injected you can use a short peice of small hose to use to listen to your injectors or, try unplugging them one at a time while your car is running and see if the motor runs rougher, if so its a bad/clogged injector...you can likewise unplug one spark plug at a time and see if that makes the motor run rougher...the idea I'm trying to convey to you is a process of elimination and the routine maintenence type stuff. Your problem dont sound too bad and you will most likely find it this way...if these dont solve you problem, find a mechanic you trust, drop the 60 bucks and have a scan ran on it, but I'll bet you can find and fix it the way I described earlier...good luck!

Your car is most probably pregnant, or having a mental break down or maybe its just a grumpy little cow that need a slap! Don't trust them! They are pure filth! Should have been drowned at birth!

*No offense to the virgin mary*

Your best bet will be removing and visually inspecting the spark plugs.

try checking spark plugs and ht leads. its cheap and easy and sounds like that could be the problem