2001 Infiniti QX4 problems please help!!!!!!!

[ownedbypandas]

Ok so my aunt has has this car for the past couple of years and she kinda ran it into the ground. She decided to purchase a new car and sold the car to me cheap! Its a 2001 qx4. Once I got it, the car ran like complete doo doo. First thing I did was I took it to autozone to get the codes read. The ECT(engine temp sensor) and misfire number 3, plus it has a horrible vibration and a huge clunk when coming to stop or taking off. So I decided to take everything apart and inspect it. I replaced the #3 coil(it was toasted, replaced pcv valve, spark plugs valve cover gaskets, intake gaskets, air filter, oil, and oil pan gasket. I also got a new driveshaft mount (carrier bearing with bushing) as well.


Start it up no problem, once it warms up....

It will idle around 800 then every once and a while die down and come back up again. The car wont rev past 2200rpm in park or neutral. Once you get up there it feels like it has a rev limiter almost.

Now the test drive....

Drove it, feels like the transmission slips a little but the sway and clunk is still there. The mount definitely cleared it up a bit but its still there.

I am stumped. Does anyone know how to test the ect or where it is located. I tried to check the maf (disconnect and plug back in while running) and it stays on. From my past knowledge of nissans if it has a bad ect it will shoot to limp mode but not sure about this car. The rear end still sways so Im just going to assume its a sway bar bushing or something.

Please help guys I need this car on the road asap.

[Towncivilian]

Are there any current codes? See LC-17 for the location of the water control valve.

What's the condition and level of the transmission fluid?

1. Drive around for 10 minutes in the city after the transmission is at operating temperature.
2. Park on level surface and apply parking brake.
3. With P selected, shift through every gear and return to P.
4. Pull transmission dipstick with engine idling, wipe clean, reinsert completely, and read level. It must be within the notched areas labeled "HOT". Check for fluid contamination after wiping on a paper towel.

The fluid should be red, and not smell burnt.

Ideally when you had everything apart you would have put threadlocker on the power valve screws as there is a possibility of them falling out and causing engine damage.

Lower control arm bushings are a common cause of wobble or sway, especially at highway speeds on these vehicles. Inspect and replace if necessary.

[ownedbypandas]

Ok so the transmission problem is fixed, it was low on fluid. The clunking is still there and like you said Town it looks like the lower control arm bushings are shot, I can grab the arm and move it and it will twist a little.

The engine seems to be better, I checked all the sensors and cleaned the maf. It idles fine now, but wont rev past 4k. And if you pull the throttle wot it will like stop there and the rpms will go down? Any suggestions?

[Towncivilian]

Sounds like a failing MAF sensor. Is the rev limit 4000, or 3600RPM? If it's closer to 3600RPM, it's almost certainly a bad MAF. You can use this MAF as a replacement.

[Empty V]

Sounds like a failing MAF sensor. Is the rev limit 4000, or 3600RPM? If it's closer to 3600RPM, it's almost certainly a bad MAF. You can use this MAF as a replacement.

That one should work. Try cleaning it first with MAF cleaner first and replace your fuel filter.

[Towncivilian]

Sounds like a failing MAF sensor. Is the rev limit 4000, or 3600RPM? If it's closer to 3600RPM, it's almost certainly a bad MAF. You can use this MAF as a replacement.

That one should work. Try cleaning it first with MAF cleaner first and replace your fuel filter.

He cleaned the MAF already. Fuel filter is a good idea though, considering the maintenance history (or lack thereof, as claimed). Wix 33023 or NAPA Gold 3023 are excellent options for around $14. See here for a fuel filter replacement guide.

[ownedbypandas]

Ok I got a update. I took all the spark plugs out to check if they were sparking all are sparking, all coils have +12 and ground. I double checked all sensors and vacuum lines. I pulled the maf off and cleaned it again and now the car is acting fine. it has the power that it didnt have before. it revs up fast and is strong. I changed out the fuel filter already. I thought the maf would have its own code. Im going to go and erase it and drive it around and see if it comes back on.

[ownedbypandas]

Ok guys need your help now. So I replaced 5 of the coils( I actually used 350z coils) but the number one i didnt change. Now I just checked to see if I had resistance between terminal 2 and 3 on the coil and i have resistance(that means its good????) I also checked the connector for voltage ground and signal and they are all there. Well now the car is throwing a different code... bank1 to lean p0171. Now I am starting to lean towards putting a new one from advance in the first one. but could that code be from the maf as well???

If so how do you check the maf itself to see if its good, I checked the signal voltage grounds etc for the maf connector and its all good...

The car acts so weird if your driving and you mash the gas it revs for a little and just sits there(no higher than 2300) and it will eventually dimmer down if you hold on the throttle...you have to let off for a sec then slowly push back on...

[Towncivilian]

If the MAF's voltages check out fine according to the FSM's reference voltages, I think you need to replace your MAF. Use the Maxima MAF I linked above.

[ownedbypandas]

I changed out the maf from a 2000 maxima, runs perfect now!!!! The engine code p0321 is still on but it runs good. it also has new coil packs as well. So Im thinking maybe it will relearn. Thanx guys for all of your help, you'll saved me hundreds of dollars. That maf was over 400 bucks from infiniti and I was able to get the maxima maf for 135 after tax.

[Towncivilian]

There is no code P0321. Are you sure that's the correct code?

I'm glad you were able to fix your problems! I assume you got the Maxima MAF at a local dealer instead of Courtesy Parts, which explains the somewhat higher price? Still beats the $400+ for an OEM Pathfinder MAF!

[ownedbypandas]

Yeah I went to a local infiniti dealer. Cost me 138 after tax, they wanted almost 3 times as much for the actual qx4 maf. The code was p1320 sorry.