m.maloney

I've been searching and reading all afternoon through threads about what may be causing the problems I'm having/have been having with my 2000 Maxima.

Backstory:

Replaced upper intake manifold and did the JB Weld fix on the power rod last fall (along with all gaskets) per the advice of a friend's shop with a vacuum smoke tester. All was well for a while after that. Codes went away, ran good, MPG was as good as it ever has been.

Fast forward a few months. Rough idle for the first few seconds at startup, no codes. Learned to live with it, I just let the car warm up before driving it. (130,000 miles is most I've ever had on a vehicle and I thought it was just a quirk of its old age)

Fast forward a few more weeks, and it gets worse seemingly overnight. Now it dies on cold starts (every time), but stays running after a restart. Barely idles, I can't give it much gas or it dies. I can hear the backfires up front if I give it too much gas while it's hesitating. I swapped coils, all were fine. Today, the CEL came back on and it is giving me the 1st and 3rd gear transmission codes, P0731 and P0733. I thought this was strange, as it shifts fine, it just runs like hell. Before replacing sensors left and right, I am now about to take out the ol' multimeter to test the MAFS and the TPS.

My question to you all now is this: Which part of the FSM will I find directions and specifications to test and recalibrate the TPS, and to test the leads for the MAFS? Or if there's a how-to thread I somehow missed, a link to that would be just as helpful.

This is the version I am searching through, is there a better one?
http://www.nicoclub.com/FSM/Maxima/2000/

Cold weather is right around the corner for us up here in WI, so I'd like to get one more season out of this car before she gets sent on her way. Thanks in advance to you all.

Cheers.

Pilm

NT2BAAH but have you looked in the sections entitled Mass Air Flow Sensor and Throttle Position Sensor? Each of these has a subsection entitled Diagnostic Procedure, that's what you want. The procedure for the TPS also refers back to the Basic Inspection subsection where it gives the TPS calibration procedure.

m.maloney

I figured out how to test the MAFS, it was within spec for all wires.

Making sense of the TPS section is a bit more difficult, but not out of my comfort zone. After eliminating the coils and MAFS, searching high and low about my transmission codes, and problems others have been having.. I think I'm going to just order up a new TPS. Is using the feeler gauges to recalibrate the closed throttle position "good enough," or is having Consult-II necessary? In which case, is bring it to the dealer to have it done recommended, or is there a method to calibrate with a multimeter that anyone knows of?

Pilm

Don't need a Consult to calibrate but before buying a new TPS I'd check to make sure it's really bad as replacing a good part is just a waste of time/money. Insert 2 mil feeler gauge and make sure throttle switch remains closed, then insert 6 mil and make sure switch is open. Then you can check linearity, make sure sensor voltage increases proportional to throttle increase.

boxersdaddy

had a rough running morning after starting my 97 se sunday. black smoke coming out of tailpipe. popped the hood and heard some noise in my MAF electrical box. tapped it with the back of a screwdriver a few times, and the car started running smoothly again. seems like i shook some 'cobwebs' in the little box. anyone know what is going on there?

Pilm

Black smoke sounds like you are/were running rich and burning the excess fuel, which could result from a bad MAF, and eventually might damage your O2 sensor if it persists. I don't know about the 97 but some MAF's have a resistor mounted in it that I suppose could come loose, or perhaps the sensor itself is loose. I'd pull it out and take a look as I doubt the tapping you did will solve the problem for long.