2000 Qx4 troubleshooting

[Jershay91!]

Hello, this is my first post here, apologies if I didn’t post it in the right place.

So I have a 2000 QX4 just replaced timing belt, water pump, radiator, and added ab external transmission cooler. Drove it for 2 weeks after that and as I was driving it one morning it lost power. It was like I was running out of gas. Since then it’s been a crank no start. I’ve heard it could be crank sensor related but the codes I’m pulling are as follows.

P0400 (exhaust gas recirculation flow)
P0325 (knock sensor 1 bank 1)
P0139 (oxygen sensor slow response bank 1 sensor
2)
P0161 (oxygen sensor heater circuit bank 2 sensor 2)
P0138 (oxygen sensor high voltage bank 1 sensor 2)
P0100 (mass or volume air flow A circuit)

Any input would be helpful!

[MisterH]

I'd start with testing the MAF sensor first as that affects just about everything. The testing procedure is described in in the factory service manual and if you have a multimeter it shouldn't take more than 10 minutes. If your MAF is faulty your best bet for replacement is the HItachi OEM.

If it needs replacing, then this is the part you want:

https://www.rockauto.com/en/moreinfo.ph ... 28&jsn=872

[Jershay91!]

I checked my MAF sensor and cleaned it. Still nothing. Even though I don’t have camshaft codes i am thinking it may be timing. I’m getting backfire in the manifold.

[MisterH]

You may want to start examining your distributor. I realize you didn't get the P0340 code which signifies cam failure, but the distributor can mechanically fail without triggering that code. It did in my case as the rotor gear started to fail and caused it to jump around; throwing off ignition timing. If your distributor is original (Hitachi) that may be what you're experiencing. If you have a scope you can test it to see what the ignition waveform looks like. See the FSM for the procedure. If you end up needing to replace it I strongly urge you to avoid buying the cheap Chinese replacements. Go OEM or try to find a rebuilt Hitachi unit, as even though it may cost up to three times the price of the $100 chinese replacements, they are much less prone to failure.