2000 AE surge/stumble

[TylerW]

Hey guys:

I sold my previous '98 T and was out of a Q for a year. I found and bought another one a while back, this one a 2000 Anniversary Edition. I like it, but it's not running exactly right.

What's going on is, most of the time the power is off at lower rpm, say under 3K. Essentially, give it some gas at lower speeds and it almost tries to nose over for a couple seconds. Then it'll recover and go on. If you gas it hard, it goes like a banshee. It's just like a carbed engine with a bad accelerator pump.

It doesn't stall. It idles perfectly. It.is.not.misfiring.I had to do both coil packs and plugs on the other car at various times and so I'm very, VERY familiar with misfires on these and it's not doing that. There's no 300 codes and it runs fine under a hard load. It's smooth at cruise speeds.

I noticed if I'm climbing a pretty steep, 45mph mountain near here in 3rd(OD locked out) that I can definitely feel the engine surging lightly. Not a miss, a surge. There's a difference. It also seems worse the hotter the temps out. Occasionally all the low rpm response comes back and it reminds me that it's not well.

The only other thing I suspect is related is that it has a long crank 95% of the time. The other car did that when it heat soaked but this one does it hot OR cold.

Your thoughts are appreciated. Don't say the CP word.

[TI-3VOM]

iam having the same exact problem with my Q, and i agree with you on it not being the coil packs because i just fixed that issue, i was thinking it might be the ks retarding the timing or even the maf, do you have any lights on the dash? my slip,tcs and check engine are on, also ive found it runs better if you switch from 91 to 93 octane every other fill up, could just be my mind playing tricks on me but it could be something in the fuel system? pump, injectors?

[3Q Jay]

check MAF.
95-99 Maxima uses identical part so they are plentiful.

[TylerW]

So I've devoted more time to chasing this gremlin:

1. I swapped in another used MAF and there was no change, so that wasn't it.

2. I thought it was heat-related, it's not..necessarily. It does run better pretty good with cold and dry air but I really don't know what that has to do with it.

3. Checked every inch of the intake tract for leaks when I did the MAF, found nothing except a deteriorated seal at the TB end, which I replaced. No change.

4. Pulled codes again and found P0325(knock sensor...surprise), P0400(EGR flow) and P0500(speed sensor signal drops out momentarily)

The P0325 I haven't dealt with yet. The other car had codes for both of them and ran fine.
The P0400 I lucked out on and it was simply the rubber hose under the transducer or whatever it is. Replaced that, cleared the code and it hasn't come back. Didn't fix the drivability issue either.
The P0500 is an ongoing problem. The speedo never drops out but the cruise does. Not sure how that might relate to drivability but I'll start another thread on that.

5. I get a strong smell of catalytic converter/ exhaust when climbing a hill or passing a car. Every time.

6. It never stalls, and never acts weird at idle.

7. The long crank issue is ongoing. So far I don't think I've seen a definitive cure for that on a Q45.

I'm going to do a KISS manuever and change the fuel filter this weekend. past that I'm going to keep driving and wait for something worse to happen or not happen. If there's no resolution within a month or so I guess I'll have to find someone who can put a consult on it and get some streaming data. I'm not going to keep throwing parts at it, not even used ones.

Thanks.