2000 Xterra Rough Idle, Stalling, & Bad Driveability
Well here it goes. Please help me.
I have a 2000 Xterra, 3.3 v6 with 4wd and 112,000 miles. About a month ago, My check engine light came on with code p0440. (minor Evap system leak) I figured the most common thing is the gas cap. I cleaned off the o-ring on the gas cap, cleared the engine code, and good to go. The car ran fine with no issues.
About 3 weeks ago, my check engine light came back on with code p0440 (minor Evap system leak) This time I replaced the gas cap. Then about a day or so later, I noticed the car having very poor driveability. Cruising at about 2300rpm, the car would sputter dropping to about 1800rpm, ten surge right back to 2300rpm, and so on and so on. When I got home, I turned the car off, then restarted it to a horrible idle. The car would idle like normal, then drop to 800rpm, then back to around 1100rpm, then down to 400 rpm, back up, and eventually would just stall out. Awful. I began looking into other possible issues. I disassembled the purge control valve under the hood, and cleaned that out (could have possibly been sticking) but it was actually pretty clean. I took off the vent valve on the side of the charcoal canister under the car to make sure that was operational, (it was). Took off the distributor cap and cleaned the points off. Checked all my fuel system hoses, found no leaks. Thought it could be just bad gas, but I was on 1/4 tank and had JUST started having problems. Went to start the car again, still had a very rough idle.
At this point I broke down and took it to a friend of mine who works at pepboys. He did a smoke test looking for the Evap system leak. Turns out the gasket under the fuel pump was leaking. But he did not at all think that had anything to do with the poor running conditions of the vehicle. The car would not act up very badly for him while it was in the shop, so he couldn't do too much to trace it. I picked the car up, and on the way home, the car almost choked out and stalled on me while going about 45mph. I barely limped home. When I got home, I turned the car off, then back on to the same old horrible idle. I re checked the engine codes (no check engine light was on) and this time I got code p0180 (gas tank temp sensor or circuit fail). WTF? So the car sat for about 4 days untouched. I went out today and started it up, and it idled and ran fine for about 5 min. Then it started choking and sputtering a bit. Eventually it went right back to its rough idle and just cut out.
The mechanic seemed to think the issue is that I need a new distributor. I have done some research and found many many different resolutions to this type of issue. I have read success stories by simply replacing the gas cap, but I have also read stories of having to replace the ECU. I am kinda strapped for cash right now, and I am really hoping someone has some insight on what could be causing this. I am very mechanically inclined, and would be able to replace or fix a broken part, but even the mechanic wasn't 100% sure the problem was the distributor. I know it's hard to diagnose a problem over the internet, but ANY help would be GREATLY appreciated. THANKS!!!!