I H8 COPS

Can anyone tell me why I'm getting micro-second pauses during acceleration? Happens often at intense acceleration. Some here have suggested that maybe it has something to do with throttle body, fuel filter, etc. etc. However, I think I can eliminate these suggestions because it only happens when my tank is less than half full. Hence, am I correct to assume that it cannot be, for instance, a fuel filter because if it were clogged then it wouldn't matter how much fuel I had? Also, car idles funny when still. RPM is at the right level but occasionally it also drops and rises unexpectedly for a micro-second or so. help?

KMax2988

Mine has the funny idle problem also. Have not been able to pin point it yet. Really started noticing it after my MEVI install. No vac leaks, everything is torqued to spec, and I replaced the IAC. Helped little. The idle doesnt drop as drastically now but still drops. As for the microsecond pauses in acceleration, dont really notice any (seems to accelerate very strong leading me away from blaming injectors or coil packs) and if I do, it's prolly me being paranoid (at least I hope so). It's good to check the fuel filter for that tho, might be a fuel delivery problem of some sort by the sounds. How many miles are on your car? 100,414 miles here. Hope this gives you some insite and hope someone can completely diagnose this problem.

I H8 COPS

I only have 50K miles on my 99 Max SE-L. It's a 5-spd.

KMax2988

With that low of mileage, I wouldn't put it past the infamous Maxima coil packs. Seen many posts where bad coil packs were to blame for choppy acceleration. This could also account for the funny idle due to the cylinder(s) with the faulty/intermittently working pack not gettin proper spark and causing an occasional misfire. In my case tho, the car has such strong acceleration that I would more look toward an injector hanging up, but even that is hard for me to comprehend as it runs so well driving and at WOT.

I H8 COPS

I am almost certain that it must have something to do with the fuel system. I'm thinking fuel pump, but this one mechanic suggested that it's some device which connects the fuel pump to the tank. This tiny device, as he claimed, actually sort of pumps fuel into the fuel pump. I forgot the name though. Any other suggestions?

MAXIN

iTrader: (5)

I believe some members solved similar problems like yours by cleaning the throttle body. As for fuel delivery: your pump could be on its way out, and/or your filter may need to be changed.

Cheapest thing, start with cleaning the throttle body, cant hurt your wallet.

I H8 COPS

That's what I am saying...it CANNOT be either the throttle body or anything of that nature (like fuel filter, spark plugs...etc.). That's because when my tank is full, the car runs PERFECT! When it's under half full, only then the problem resumes. That is why it cannot possibly have anything to do with a throttle body or a fuel filter being clogged.

Naujik

Check your fuel pump?

I H8 COPS

Can I check the fuel pump myself? If so, how? I don't want some sweaty mechanic to do it and charge me $100 only to tell me that it is indeed fuel pump...or worse yet...tell me that it's not.

rmb

Maybe something nasty in your tank? Like water or something that is floating near the top. When the level gets down there, some of it gets sucked in the pickup tube?

Run it way down and add a LOT of drygas (pure isopropyl alcohol). Might help.... Cheap to try.
-RMB

White96MaxSE

I once hooked up a fuel pressure gauge directly into the fuel line under the hood just to see what it was at idle, and how long it took to drop after I turned the engine off, etc.

It should be around 32 PSI, I think. Anyone know exactly?

An inexpensive fuel pressure gauge can probably be found for this purpose. I didn't spend much, but I have had the gauge for so long I forgot where I bought it.

White96MaxSE

Zirafa

Could it be the TPS (Throttle Position Sensor)? They are known to go bad on 4th gen.
Check this:
http://vbxmaxima.8m.com/tps.html

njmaxseltd

iTrader: (19)

Sounds like a misfire. Check your plugs and the coil packs.