2001 maxima se erratic idle

[Dansmaxima]

My 2001 SE has idle control problems. It's stalling or running way too high, sometimes fluctuates between 1500-1800 rpm. Swapped out the iacv-aac idle motor. I put in all new O2 sensors but they're universal Bosch sensors. Could this be the mafs? No codes on for anything. Previously, code for catalyst keeps coming up every 200 miles or so. Really want to narrow this down. 95k on it.

[lightsout]

i had a similar problem, and i replaced both the crank sensor(just below the pulley near the oil filter)...and the camshaft sensor(on the front left of the engine, on the chain cover/plate, near the horn).

i also replaced all the O2 sensors, all the spark plugs, all the coil packs, and Idle control unit( http://www.autozone.com/N,3168...4.htm ).

u need to take your car to a nissan/infinity dealer and have them scan the ECU with their computer b/c it tests EVERY sensor individually for small malfunctions! it will cost you $80-$120...but it will make things clearer. Then you can come back to NICO, and we will help you figure out what needs to be done!!

[Ketchup83se01]

If it is your maf then the car will not go past 3500rpms, also the maxima sensors are bosch anyways

[Dansmaxima]

Well, I'm still at a loss. I don't want to give up and get ripped off by a mechanic that probably knows less than I do by now. Junkyard guy told me if I disconnect the MAFS the erratic idle will settle down and that will tell me if it was the mafs. It did, but at 1600rpm. He thinks it is a vacuum leak, I poked around for a long time looking for vac hose problems. I don't want to keep buying junkyard sensors- my scanner is a Memoscan U381. I hope it is a decent scanner. It may be time to limp the car into a dealer and see if they can diagnose it. Very frustrating.

[NutriaforBreakfast]

Idle problems are the toughest so dont feel bad

You gotta do everything from checking the sensorsto a compression leakdown test sometimes

[lightsout]

check engine light???? is it throwing ANY codes, if so, what are the codes?

[Dansmaxima]

Thanks for all the replies! No, no codes. It starts cold and idles way too high. When it warms up it starts going up and down between 1200 and 1600 rpm. I had my head in that engine compartment for a long time looking for a vacuum leak. Maybe pep boys sold me the wrong O2 sensors.I'm going to see if I can find a local dealer with a decent reputation and ask if they will diagnose it.

[lightsout]

i cant think of anything other than listed above, except maybe a twitched ECU?

Think back, did you do any work on your car before all this happened? did you do the IACV and 02 Sensors before this happened?

Did you check all your fuses under the hood and in the dash?

i would recommend:you could try reseting your ECU by removing the negative battery connection, and leaving it off as little as 10 mins, or as long as overnight...then reconnect it, and see if ANY small thing has changed.

[Dansmaxima]

Thanks again for the interest! I can clear the codes now with my scanner. I did put a battery charger on the car a while back and noticed the voltage was a bit high. I hope I didn't fry the ecu somehow. My recent O2 sensor replacement was to try to rectify my previous sec light coming on periodicly. I'm looking for the reciept on the code it showed, it was one of the catalyst codes. Maybe my pre -cats are shot? The cat? I wouldn't mind replacing all that if I had time and $$$. Do you have to pull the engine to replace precats? Do you have to buy new exhaust manifolds at some outrageous price? I've been checking consumer ratings of local Nissan dealers and haven't found any positive service experiences- I'm paranoid and afraid to get ripped off. I need to study the factory manual and my scanner more thoroughly and test sensors with my multimeter for voltages, etc. as much as possible......

[lightsout]

you don't have to pull they engine for any of this, you will need jack stands so you can work comfortably under the car.

i'm not sure if you need to buy a new manifold quite yet b/c we havent put our finger on it yet.

which 02 sensor did you replace?

[Dansmaxima]

Thanks again! I replaced all O2 sensors. I tried to save $$ by getting universal Bosch sensors. The 2 white wires are not marked on the 3-wire or 4-wire sensors, so I assume there is no polarity when attaching them to the connectors. The three wire has a black, and the four wire has a black and a grey. Bosch provides a nylon compression type connector to attach the wires together- I'm certain I utilized these connectors correctly.

The car is going in to a local Nissan Dealer Monday for diagnosis. I'm in NJ-every mechanic seems like Tony Soprano to me....I really want to get my car back to life, detailed, waxed, polished, and presentable!!!

[arkangelgabriel]

hey there. well i have a 2001 nissan maxima GXE, just bought it bout 3 months ago. the car had the service engine soon light on. Autozone pulled out a code, said the sensor 2 bank 2 was bad. changed it but it didnt fixed the problem... its actually gettin worse. the car runs bad sumtimes, no acceleration and it losses power entirely while running and then it recovers after 5 seconds or so. lately it has been loosing more power than usual. i changed spark plugs also. i just bought the maf sensor which might be the problem. it looks like we have more or less the same problem. the car iddles high when cold (but its actually normal) but it settles back down n it runs fine. it will not go pass 3500 rpms or so.... and when the gas pedal is pushed down the car wont respond, it will stall. I too thought about a vacum leak, but didnt find any. i unhooked the air flow hose and cleaned the thottle body intake ( if you do dont spray the thottle body cleaner right inside, just spray a little and wipe). so right now im just waiting for the maf sensor to arrive. ill keep you posted to see if that fixed the problem.

[Dansmaxima]

Hey, I haven't been here since I sold that car at a great loss. The guy that bought it knew a Nissan tech. You will need to find an honest Dealer and insist the car is diagnosed by a factory trained technician using the ConsultII equipment. If you try to fix it yourself you will keep swapping out parts and very likely go crazy like I did. Two Nissan Dealers tried to rip me off, and could not fix it due to incompetant mechanics. I complained to Nissan Consumer Affairs and got a so sorry form letter back months later.If you do keep going consider the power steering sensor, or possibly a warped intake plenum.My car was a lemon and a jinx, impossible to fix at home. The guy also told me use only genuine Nissan parts, so be prepared to pay four times retail. Good luck!