Do any car mechanics in this forum work on Nissans?

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Originally Posted by jmg8550

That maas air sensor cleaner works. However, a bad mass air meter will cause the engine to fall on its face when trying to accelerate. Should idle fine though. I really would like the codes read, or a scanner hooked up to read the data from the computer.

Sounds like the stealership is just throwing parts at it, and wasting your money. It also sounds to
me that some real diagnostics are going to have to take place, not just educated guesses and a lot of parts.

Lean fuel trims can be caused by lots of things, bad O2 sensors, vacuum leaks, malfunctioning mass air sensor, etc.

If you just had a timing belt replaced, your cam timing could be off a tooth. Any major repairs like that recently done?

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This issue began when the car would not upshift (usually after braking at a stoplight or for slower/slowing traffic)- of course, the problem was intermittent. A week later, the check engine light came on and we took it to Goodyear. They ran a diagnostic, replaced a sensor and said that was all they could do. We took it to a transmission specialist but he couldn't find the problem. The end of July, the check engine light came on again and we took it to Brakes Plus. They replaced the brakes, the calipers, an engine mount, and a control arm. They ran a diagnostic and came up with a code p0720 and told me that the revolution sensor may possibly be the cause.

So we took it to the dealer, and they found a short in the revolution sensor, replaced it and reset the control unit. They wanted to also replace the air flow meter the air filter, and ECM program (which apparently only the dealer can do?), replace the power steering feed hose and pressure hose because "they're leaking". Nobody else told us anything was leaking, and the damn stealership (thanks for the new word, jmg8550!) wants a minimum of $1500 for this. We're completely tapped because of all of the trips to different mechanics, and we had to get new tires before that.

Could be the "idle air learn". I worked on a Nissan where I had to do a idle air learn procedure! Car ran fine, until I disconnected the battery to replace the air conditioning compressor. Car ran like crap. Did the procedure- fixed it! You just about need a stop watch to do it correctly. Hope this helps!

http://nissanhelp.com/diy/maxima/pro...e_learning.php

A P0720 code is a revolution sensor malfunction, possible causes: faulty sensor, open or short in the wiring, or high resistance in the wiring. It is also called the vehicle speed sensor. It will cause shifting problems, and an erratic or improper reading speedometer. On your car, the sensor is very easy to replace. Look up how to do it on YouTube. Looks like it would take maybe 30 minutes. Cleaning a mass air sensor is also very easy. And replacing it isn't much harder. You should be able to do both sensors yourself with ease.

The revolution sensor was replaced through the dealership, and so far, the intermittent upshifting problem has been fix. (knock wood) This was before I thought to check with the hivemind here, and realized this is something I may be able to do myself. Maybe. I mean, I've never done anything like this before, but I've got Youtube videos and the collective wisdom of the car guys here. ;) I can't fail!

A lean fuel system will turn your engine light on after it reaches 25% fuel enrichment. Anything under that, and you shouldn't notice the engine running rough. Mileage? When was a tune up done last? Rough engine running on an OBD2 engine (any vehicle '96 and above) will turn a light on eventually. Especially misfires.

I think we had a tune up done within the past year or two. The mileage is @ 190K, maybe a bit more. The ragged running was a surprise for us both, because it seemed fine after leaving the dealership. Because of that, he's still driving my Jeep. [Rant2]I want my Jeep back, dangit! I'm going to go start the Nissan up in a little while, and see if it idles rough again.

A thousand, thousand thanks go out to jmg8550 for taking the time to speak with me about the intricacies of this issue, the possible things that could be wrong, and many options to rectify the problems...and in such a way that I could follow and understand. You are a wealth of knowledge, and I hope they pay you well and appreciate you at your job!

Here is what happened:

I went to O'Reilly's and picked up a can of CRC MAF cleaner, an air filter and a package of various-sized star bits because Nissan uses those instead of regular sockets. Bastards.

I used one to start to loosen the bolt, and promptly dropped the damn bit into the engine somewhere.

Let me take a moment to rant: who the hell decided to make those bits BLACK? The rest of the engine is shades of gray and black and dirt- how the hell are you supposed to find a bit if it should drop into the engine? What's wrong with making it blaze orange? AND, by the way, would it be so hard to magnetize the bits, so they remained on the socket wrench to begin with? I've got enough things to worry about without having to add the perils of gravity to the mix. Criminy.

So, of course couldn't find it. I looked under the car, but it was not in there. I used 3 different flashlights and tried to spot it from the top of the engine. No luck. Dammit.

So I used another bit that didn't fit AS nicely, and it still worked. I didn't pull out the entire sensor because that would have entailed removing more stuff than I felt comfortable with, but I pulled out the sensor (CAREFULLY). The sensor has a wire assembly harness attached to it that just would not come off. It has a little lever thing that I pushed and (CAREFULLY) pulled and did everything I could think of, and it just would not come off. I tried to find a Youtube video for it, but all I came across was some idiot explaining about the wire harness and then he let his camera drift to look at the underside of his hood while he removed the wire assembly. After reading the instructions on the can of cleaner, I decided that I would be incredibly conscious of where I was spraying, and avoid getting any of the wires wet. Because the wire assembly was still attached, I laid several layers of newspaper down, and pulled a paper bag over the sensor. I put on latex gloves, and proceeded to spray all sides of the sensor a couple of times. It didn't look exactly like what the Youtube video showed, but it was close enough and I could see the guck on the metal bits. The paper absorbed the cleaner and dirt. I then set fresh paper down and let the sensor sit on that until it was dry.

I put the sensor back in place, took the star bit and began screwing the bolt back into place...and dropped that bit into the engine as well.

After a good lo swearing session, followed by a long hunt for either one of them, I decided they'd fall out when they were ready and not one moment before.

I proceeded to use the star bit that hardly fit at all, but still worked...and got it back together. I also changed the air filter.

The car started up, and then stalled out. After a second start, it purred like a kitten and drove as it should. We took it around the neighborhood and it did fine!

Thank you, car guys, for sharing your knowledge. I realize this may not be a big deal for you, but for someone that knows how to check the fluids and that's about it, this was enormous.

I just hope those stupid bits fall out soon. Preferably in the driveway so we have a complete set again.

Completing tasks (that we otherwise would never have considered) for the first time is very liberating.

Glad I could help. Hope it stays running well for you.

I've used the Nissan dealership in 104th for a few things and they were awesome. I did make it clear that I only brought it in because I was too busy to do it myself though. Makes me mad when they try to rip off people that don't know cars.