I have a 99 nissan altima that has roughly 98000 miles on it. I bought it from a used car dealer, and noticed the check engine light was on and ran a little rough. Took to auto parts place and they checked the code and said cylider 2 was misfiring. So I changed the plugs, wires and cap and still runs rough.

And I noticed that when I have the ac on , the car runs rough and acts like it wants to stall while I'm at an idle or when I'm slowing down to stop. But idle goes up a little ( not much ) when I shut the ac off. Car seems to run fine when I'm moving , just occurs when at idle or slowing down.

Can anyone help me with this? :confused:

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Originally Posted by tpatowman01

i have a 99 nissan altima that has roughly 98000 miles on it. I bought it from a used car dealer, and noticed the check engine light was on and ran a little rough. took to auto parts place and they checked the code and said cylider 2 was misfiring. so i changed the plugs, wires and cap and still runs rough.

and i noticed that when i have the ac on , the car runs rough and acts like it wants to stall while im at an idle or when im slowing down to stop. But idle goes up a little ( not much ) when i shut the ac off. Car seems to run fine when im moving , just occurs when at idle or slowing down.

Can anyone help me withh this? :confused:

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It possible you've got a sticking or failed fuel injector on number 2 cylinder. Either of these would cause a misfire code.

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Originally Posted by CaptainRich

It possible you've got a sticking or failed fuel injector on number 2 cylinder. Either of these would cause a misfire code.

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Well I think I fixed that code with changing the wires etc, and had the code cleared... stayed off for 2 days then came back on ( parts place said that it has a dealer code now and couldn't retrieve it ).

Im more interested in figuring out what would cause car to idle low and run rough. I have put in injector cleaner twice to try and fix problem. I had a friend tell me something about an ac idle control sensor, or something like that might be bad. That it might not be making my idle go up when ac is on... does that sound right?

Yes, when the air conditioner is on, the (IACV-FICD) solenoid valve supplies additional air to adjust to the increased load. It sound like that isn't working.

But the stuff you put into the tank is ineffective for freeing up a stuck injector. Concentrated solvents need to be intorduced to the fuel system proffesionaly. If the stuff you use in-tank were strong enough to free up stuck injectors, it would likely damage fuel system components.

I agree with the person who stated that you need to change your fuel injectors on cyl 2... it has a lot to do with that... my boyfriends truck has the same problem, my dad is a mechanic and that is what we were told about the truck because his is misfiring on cyl 2 and 5... and the fuel injectors need changed.

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Originally Posted by tpatowman01

i have a 99 nissan altima that has roughly 98000 miles on it. I bought it from a used car dealer, and noticed the check engine light was on and ran a little rough. took to auto parts place and they checked the code and said cylider 2 was misfiring. so i changed the plugs, wires and cap and still runs rough.

and i noticed that when i have the ac on , the car runs rough and acts like it wants to stall while im at an idle or when im slowing down to stop. But idle goes up a little ( not much ) when i shut the ac off. Car seems to run fine when im moving , just occurs when at idle or slowing down.

Can anyone help me withh this? :confused:

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I just want to thank everyone who posted answers on here. It turned out that my motor mounts were bad. I've replaced the front and back mounts, and it runs a lot better now. The 2 sides ones need to be replaced but that will come in time.

Thanks again.