Hi guys,

Bought a new to me 2014 Sentra 6 speed (yay!) 3 or 4 months ago so I could get rid of my 2017 Sentra CVT. It has AC problems when I bought it and you guys helped convince me that I needed to replace the AC compressor, condenser, and flush the whole system out. It's been cranking along super cold here in Arizona for almost 2 months now thanks to that. Did it for right around $270, so money well spent!

Anyway, a new issue has now arisen... Under both acceleration or holding a steady speed, the car will intermittently slow down just like I'm letting off the gas. Sometimes, it will recover on its own and go back to the same speed or continue accelerating. Other times, it will continue to slow until I release the gas pedal and hammer it down at which time it will accelerate. There were very few occurrences for 2 weeks up until Thursday this week when storms rolled into town and humidity went crazy high for Phoenix. Don't know if it's related, just thought I'd mention it. As for gas, it's been happening on multiple tanks of gas and we buy at various places, so it's unlikely to be the cause.

Only thing I've tried so far is swap out the gas pedal assembly with the original from my 2017 that I had replaced trying to rule it out as the source of a different problem. I'm going to replace the air filter this weekend (I haven't yet since I bought it) and clean the MAF. I may just buy a low mile replacement throttle body from LKQ to rule that out since they're only $40.

Anyone ever experience this and figure it out? Any other suggestions?

AZSentra wrote: ↑

Sat Aug 20, 2022 8:10 am

Only thing I've tried so far is swap out the gas pedal assembly with the original from my 2017 that I had replaced trying to rule it out as the source of a different problem. I'm going to replace the air filter this weekend (I haven't yet since I bought it) and clean the MAF. I may just buy a low mile replacement throttle body from LKQ to rule that out since they're only $40.

Anyone ever experience this and figure it out? Any other suggestions?

Nissan APP's almost never go bad, so I'm not surprised that wasn't it. There are a limited number of things which can go wrong that the ECM can't verify. Since it's happening intermittently while underway, it probably isn't the MAF or fuel pump. TB's usually stick at the bottom and not on the highway, and in any case that would throw codes. So the most likely culprits are a cam or crank sensor starting to go south but not flatlined yet, and the ECM doesn't know what to do with the inconsistent signal.

VStar650CL wrote: ↑

Sat Aug 20, 2022 8:44 am

So the most likely culprits are a cam or crank sensor starting to go south but not flatlined yet, and the ECM doesn't know what to do with the inconsistent signal.

I never even thought of one of those being possible. So you think that my releasing and pressing the gas pedal has nothing to do with it?

AZSentra wrote: ↑

Sat Aug 20, 2022 8:53 am

I never even thought of one of those being possible. So you think that my releasing and pressing the gas pedal has nothing to do with it?

Failing Hall sensors can do some of the goofiest and most inexplicable things imaginable. I recall one R51 I worked on where the left bank cam sensor was reading a full 24 degrees out, but only between about 1500 and 3000 RPM and not every time. Go figure, but all I can really tell you is that magnetism is invisible. If you have a streaming scanner that can read cam angles, put up the cam along with the engine RPM and see if either one of them gets weird when the problem occurs.

VStar650CL wrote: ↑

Sat Aug 20, 2022 9:11 am

If you have a streaming scanner that can read cam angles, put up the cam along with the engine RPM and see if either one of them gets weird when the problem occurs.

No such luck. I'll probably just spring for a couple online and see how it goes. Thanks for the input. I'll let everyone know how it goes in a couple of weeks.

I got busy with house projects, so this got postponed, but I did pick up an air filter. The one I pulled out was very very dusty. I cleaned the MAF sensor as well with MAF cleaner and have been driving it for the last 12 days without issue. Don't know if it's working for some other reason or if the problem was resolved with the cleaning of the MAF sensor, but for now I'm not going to do anything else. I'll update in another month or so...

Just an update... no repeat with the deceleration issue since cleaning the MAF and replacing the air filter and we drive the car virtually everyday, with two cycles of engine warm up and cool down at least half the week. That's over 2 and 1/2 months without a problem, so I'd consider it fixed.