I have a 91 maxima gxe, auto, v6 3.0L with about 290,000kms.

It has very rough idle when in park or sitting in D with the brake on, when driving its not bad. The injectors aren't the best and i run injector cleaner about every 3rd tank of gas. I replaced the ignition coil, plug wires and spark plugs recently. Made no difference with anything.

This is my beater, but i'd like to keep it running as smoothly as possible and for as long as possible. Does anyone have any tips on what i should check out on this car that might be the cause of the rough idle.

I've only had it since November and stopped driving it at the end of April when i took my other car out of storage.

I have no idea when the timing belt was last done. Battery, alternator are both new. Fuel pump and fuel relay are both new.

 

Do the TB ASAP

 

I have a 90 SE Manual, and have the same problem. And to be honest, it very well could be your injectors. I used to run cleaner through mine, and come to find out it didn't help it any. I lost 2 injectors to the Nissan brand injector cleaner. Also, watch what kind of fuel you run. Up here they have the additive Ethanol to the 89 fuel. That stuff will kill your injectors faster than you can believe. I had the 2 injectors replaced, and didn't have a problem. Until I brain farted one day and put in the 89 with ethanol. Now my rough idle is back.