Knock sensor causing serious running issues?

[KosanFalcon]

Hey all, having some serious running issues and I think they may be related to the knock sensor code my QX4 is showing.
I found a knock sensor relocation video and want to try it but I talked to a mechanic I know and he said he doesn't think the knock sensor could be my problem. I have a 1997 Infiniti QX4, 223k miles. Just trying to be sure before I waste more money and time... Could a bad knock sensor be causing serious losses of power when driving, rough idling (especially in D more than P or N), and even stalling out when coming to a stop? Also has gotten worse lately; in the past giving it more throttle and making it downshift when it was getting bogged down would help. Now if it's getting bogged down and accelerating really slowly as it's doing and I give it more gas, it will jerk sharply as it gets severely intermittent surges between accelerating strongly and loss of power completely. It's even stalled several times when doing this.

[rgk]

Are you showing any other engine codes, or just the knock sensor code?

[KosanFalcon]

Just got the codes read:

P0300- Random multiple misfire
P0325- Knock sensor condition
P0505- IAC circuit condition or idle speed higher/lower than expected
P0171- Fuel injection system too lean (bank 1)
P0174- Fuel injection system too lean (bank 2)

[KosanFalcon]

So off the top of my head (not a mechanic) it's seemjng like either the knock sensor and/or vacuum leak.

How do I go about testing for a vacuum leak?

I'm basically trying to find out what's really wrong for as cheap as possible (surprise surprise haha) because I have to replace my windshield to pass inspection and I'm trying to decide if it's worth it to keep going on this. I feel like if I can get this issue fixed it'll be fine for hopefully a little while because when it's running fine it's really running great and smooth for 223k.

[vonscorpio]

Haven't had a knock sensor issue with the XQ4, but my I30 had a bad KS and all O2 sensors failed at the same time and all the associated SES codes with those sensor failures. Ran relatively well, a tiny bit underpowered compared to how it ran after I fixed everything. Never stalled, or bogged down.
Your symptoms sounds more like a mass air flow sensor or fuel filter. Or both.

(edit) Not saying the KS isn't bad, but just most likely not causing the stall.

[KosanFalcon]

Just replaced the MAF about 1 month ago, and fuel pump and filter were in the last 3 months or so.
Lol It's not making it easy on me.

I already bought the knock sensor so I'm gonna relocate it and see if that helps, also check for a vacuum leak.

[atraudes]

Kinda sounds like a misfire to me. You can test whether a cylinder is firing by pulling one spark plug wire at a time. If it stumbles or stalls, that spark plug is doing its job. If there's no difference, you found it. I'm not super familiar with the distributor systems on your car, but some part of the distributor (or maybe the spark plug wire or spark plug) is likely bad.

The fuel filter is probably worth looking at, but if that was the problem, it would simply fall on its face when you give it throttle. It would have to be REALLY clogged to cause the kind of problems you're describing, and would happen gradually over time. If the MAF sensor was bad, I'd expect it to throw a code.

The knock code is probably a direct result of the misfire. Once you get it squared away, one or more of the other problems will likely resolve themselves.

[vonscorpio]

I went through three MAFs before finally getting a functional one for my M30. And I never got a code out of it - granted its OBD1...

[atraudes]

Hm, good call. Did you determine they were bad by testing them with a multimeter?

[vonscorpio]

Hm, good call. Did you determine they were bad by testing them with a multimeter?

I don't have a good multimeter. It was a lot of helped from users gsf1200s and fourdrinie on this forum and the fun of trial and error. I was able to return one of the MAFs, but now I have two defective units lying around. I plan on experimenting on a DIY repair, assuming their failure is due to something simple like soldering coming loose.
I'm still curious how the new KS helped KosanFalcon's QX4...