Here is my original post (well, my questions on another guys post, sorry!)

http://forums.maxima.org/7818050-post37.html

The update is that I took it to my mechanic after I couldn't fix it. He had it for a couple of weeks and finally diagnosed it as carbon buildup. I think he blew out the throttle body and called it a day. While still in his driveway it took me three times to start it, having to give it gas like it had a carburetor. It would turn over and start, just not keep running. Finally I held it at around 1000 rpm to keep it going. This is how it has been since December. Every time I start it I have to 'warm it up' until it gets up to temperature or some other condition that I'm not aware of is met. Now that it is warmer outside, the time it takes to warm up is shorter, but still necessary. The reason for my post is that I rode it out through the winter just to get to warmer weather so I could go at it again. Now that its hot out, I need to use my A/C, which causes a different problem. Sitting at an idle, like at a stop light, if the A/C is on, it seems to cause too much of a draw on the engine and severely dampening it or even killing it. I can't run around with no air, so I have to figure out what is causing the underlying issue once and for all. Who has ideas?

FYI, I did a Seafoam treatment and blew a bunch of carbon out the back. I also did the oil and gas treatment as well. Additionally, I think I hear a rush of air, like a hissing sound, when I rev it up from under the hood. It makes me wonder if there could be some sort of air leak or vacuum issue. Would that go along with my issues as described? Looking forward to your help, you guys are great.

 

Do you think it might be about time to start thinking about O2 sensors?

 

Replace the maf and replace both primary O2s.

Intakes make a hissing noise (well, I can't remember if stock airboxes do LOL). That's normal, but of course that doesn't mean there can't be a leak, but if you didn't touch anything then there shouldn't be.
Check the vacuum hoses for breaks, especially to the IACV. Spray some ether or w/e around the upper IM edges, egr, etc, and see if idle changes.

You have to do basic troubleshooting or you'll never find the problem.

 

+1 on the vacuum leak. I'd definitely check that out before anything else. Using throttle body cleaner will work too - idle will decrease if it gets pulled into the IM.

 

Check for any vacuum leak and the IACV condition. Sounds like others are pointing you in that direction as well...

 

I'm sure its my lack of experience relative to others here, so I don't understand how the O2 sensors would cause either my need to gas the car to keep it going/warm it up, or how they could cause my A/C to depress the engine? Can someone elaborate? Thanks.

 

Did you try the ECU reset and idle relearn procedures?

 

I would definitely try that if I knew how. Do you by chance have any instructions?

 

UPDATE:

I did the Accelerator, Throttle Position and Idle relearns. It seems that most guys who have done this have had a high idle condition, whereas mine was a low idle/won't stay running condition. As soon as I unplugged the TPS the idle went up as expected, and once reconnected it sat at 700 or so and seemed fine. I then went for a ride and discovered a very noticeable slamming when shifting from 1st into 2nd (AT). That happened a couple more times on the way back from the short ride. I went gently through the gears once I stopped, turned it off for a few minutes and then tried again. No slamming of the gears, and I got up to about 4th at around 45 mph. Additionally, the A/C doesn't seem to be bogging down the engine quite as much as it did at idle, so that may have been resolved with the reset. I still have to rev up the engine while starting, though; it won't just start and idle.

Can someone elaborate on why I should be looking at the O2 sensors? The codes I have are 0138/0139 and 0159/0160. Even after the engine is up to temperature, if I turn it off I will have to give it gas and rev it for a short time before it will idle when turning it back on.
Thanks!

 

The codes are O2 sensor codes.

Read this link that is in the stickies:

http://forums.maxima.org/5th-generat...on-issues.html

 

I've seen cars run grotesquely rich as a result of dead O2 sensors (low 10's AFR). May or may not be your issue since at some point, too much fuel will bog down and perhaps even shut down.

I have my primaries disconnected and my secondaries plugged into my primary ports, and I run rich at 1600 and below if part throttle, but not enough to make the car die.

 

Yeah, I had horrible mileage over the winter, mainly due to having to warm up the car for so long at a time, or so I thought. I'm talking like 25% off. However, it seems that my mileage has gotten much better since doing the Seafoam treatment, and probably due to the warmer weather too.

Earlier I said that I thought the idle relearn had solved my low idle problem. It didn't. The A/C still severely dampens the idle when I come to a stop.

I still don't know why the O2 sensors would cause these issues. The O2 sensors that are showing codes are both rear sensors; B1S2 rear -white and B2S2 rear - red. Are these the primary ones or the secondary? Should I plug the fronts into the rears to see what happens? I see where they are plugged in all four in a row on the front of the engine. Which one is which?

 

Thanks, I did know these were O2 codes. My codes are all listed in blue on that page indicating that I can follow the links to more info but the links have been corrupted and go to some random conversation between some guys about a sticker or something.