Won't go faster than 20mph
 

Hey all. I lurk here whenever I need to diagnose something and now I'm finally creating a thread because I have no idea what's going on.

The symptoms:
-Automatic 2002 Maxima SE won't go faster than 20 mph
-Gear does not shift once I hit 20 mph
-Stepping on the gas at 20 mph is like stepping on the gas while neutral and just increases rpm
-Can shift into reverse
-Can shift into neutral and feel the 'bump' for when gear changes
-Check engine light is NOT on
-No other visible or discernible issues (granted I'm far from a vehicle expert)
-Happened right after changing from Park to Drive at a stoplight
-Weather is pretty hot and this occurred during a drive in hot weather.

I've been reading and there seems to be a lot of discussion with similar symptoms but I can't find a concrete solution.

Anyways, would appreciate any input on what's going on. Thanks for the help in advance.

Mass Air Flow Sensor...

...it's in limp mode, reason for bogging and not allowing for increased acceleration or speed...

...replace it.

Damn. That was easy. :laugh:

Luckily for me, I already have experience changing this thing since this generation Maxima seems to be known for having problems with the MAF.

Btw, should the sensor be replace with the Bosch generic or something else? The last thing I replaced on this car was the MAF and it was with the Bosch. Is this thing not reliable or something? I'm reading a lot of complaints online about it.

I just replaced mine on monday after 130K of use (assuming the previous ownder didn't change it-218K of use).

Seems like many people have different experiences in terms of how reliable the MAF is. One thing I've noticed, aftermarket MAFs are junk and don't last long.

you can get the cheaper(90 at courtesy nissan) 00-01 MAF and swap over the thermistor on your current MAF. There is a write-up on how to perform this swap, just search for it.

If it turns out to not be the MAF, look into the RSS, you have several of the symptoms of that going south also.

Got mine from NAPA (cuz it's a block away from me and I get discounts there) . It was the '00-'01 model and I swapped the thermistor from my other one. 2nd time it went bad in 176k miles, so not too serious an issue to me.

That part of description bothers me - I thought limp mode wouldn't allow rpm increase. Do rpms increase all the way to red line? If so this would mean slipping transmission.

Nah, that's not necessarily true. When my MAF went bad on my 01 Auto SE, the first symptoms I had were an increase of RPM's without any forward moving response from the car. Seemed like the tranny was slipping. But the next day, it wouldn't go past around 4k rpm with the throttle floored. Ordered an aftermarket MAF and it performed great for a week or two, then started going back to ****. Finally just went ahead and bought an OEM MAF and never had a problem with that ever again.

Did you ever find out what it was?

His last post was in 2012. You may need to wait a few years for his reply.