Sorry guys, I posted this in another part of the forum, and wasnt sure if it was the correct one so I'm posting again...

I have a 2001 Xterra SE V6. Was wondering if someone could help me. Lately my truck has had a very rough idle while I'm stopped. The whole truck shakes. Most of the time when I start it, my xterra almost stalls, in fact it has a few times. The RPMs go up and down on the gauge. It also has a very bad "pingiing" problem while I'm driving.
I changed the spark plugs and the fuel filter but the problem still persists. I have even tried fuel injector treatment and a higher octane with no luck. I have read it may be the EGR (Exhaust Gas Recirculation) Valve, but before I go and spend the money for it (around $145) I want to make sure this is the problem. Has anyone had this problem? And would it be hard to replace this myself? Any help would be GREATLY appreciated.
I also forgot to mention my Service engine soon light is on. I took it to an auto dealer when it came on and they told me it was the "heat sensor". I'm not trusting them, because at the same time I took it in because my one wiper wasnt working. They charged me $80 saying they replaced the motor. the next week my other wiper went. this time i went to do some investigating. I didnt realize how easy the plastic cover popped up at the base of the wiper, turns out it was a loose bolt. Instead of just tightning the bolt they replaced the motor.

Problem 1: Lately my truck has had a very rough idle while I'm stopped. The whole truck shakes. Most of the time when I start it, my xterra almost stalls, in fact it has a few times. The RPMs go up and down on the gauge.

The idle RPM should be 700 plus or minus 50. I'm betting that yours is lower than that. It's starting to happen on a lot of older trucks including mine from time to time - and i'm not sure exactly what the culprit is. I suspect the idle air control valve (IACV). At any rate, when I get around to it I'm gonna take a can of carb cleaner and clean out my intake area really well and see if that helps.. I dunno.

Problem 2:
It also has a very bad "pingiing" problem while I'm driving.

Try checking your timing with a timing light. You set the timing old-school on these trucks - by loosening the bolt that locks down the distributor and twisting it a bit... search for 'timing' and you'll find a few threads describing how to do it and what to set it to. On my '00 it is supposed to be 15 degrees BTDC. On the newer ones (don't know what year this kicks in) it is 10 degrees. Also, some people have found out that their "pinging" problem was not pinging at all - but loose rattling heat shields.

Problem 3:
I also forgot to mention my Service engine soon light is on.

Take it to any auto parts store and get them to read the actual error code for you (they do it for free). Then tell us what the exact code and description is and we can help you more.

The wiper motor thing seems to be typical of places these days... they don't know shit - and they don't care - they just want to find something they can charge you some $$ for... and if what they do doesn't fix the problem then no sweat! They'll just charge you more later to "fix" it again!

thanks for taking the time buddy, i'll look into what you said. I had already planned on taking it tomorrow to get a computer to read the code )the last place said it was a heat sensor)

There was just another post about this... turns out the O2 sensor is called a "heated oxygen sensor" - so that's probably what you had

Problem 1: I think you hit the nail on the head. Some Seafoam or carb cleaner may help. If you're brave taking the upper intake off and cleaning the IAC would be better but that is a lot of work.

Problem 2: When setting the timing you have to disconnect the TPS. Then set it as above.

Problem 3: +1

Do you have a workshop manual for it?