Hi guys,

Tried searching but couldn't find anything on the forum. Did anybody experience a fluctuation of the rpms when braking really hard and the car has achieved a full stop? I have noticed it a few times and the rpm needle moves back and forth between 700-400 rpms for a brief period as if the engine is about to choke and shut down.

 

that's happened to me a few times; especially driving really fast, and then coming to a dead stop. i felt the engine shaking for a fer sec and then went back to normal. dont know what is it but it happens not too often.

 

I've noticed the same thing on my 350 as well, but it usually doesn't come after I've come to a complete stop from hard driving. I've been sitting at stop lights a few times and I'll notice that the RPM's drop, then come right back up. Haven't really had any problems with her though (knock on wood).

 

probably concerns the maf sensor. One thing I've learned is that that little sucker is INCREDIBLY sensitive.

Is your intake stock? Moving the maf sensor from the stock location can cause a whole host of issues with decreased expected flow or out of range maf vs map sensor values....ESPECIALLY at idle.

For instance, I've moved my maf sensor to a distinct location on the pipe and went through 3 intake designs before finding the exact mounting ANGLE of the maf sensor for the IDLE air flow to still provide sufficient flow.

 

The intake in my 250 is stock as well, but I guess it might be the maf sensor. Not that it has caused any problems, it's just worrying seeing that sudden reaction after having stopped from the hard braking Thanks all for responding

 

How many miles on your car? It wouldnt hurt to clean your maf sensor with SPECIAL maf sensor cleaner. You can pick it up at any auto parts store, but be SURE its maf sensor cleaner. Other cleaners can erode plastics and other sensitive parts.

 

something similar happened recently. i was on a cold start and i broke from 40-0 really hard. it felt like the engine just shook and my CEL went on.
i pulled over turned the car off then turned it back on and the CEL was gone. o.o
scary..

 

you probably had a p0101 cel

A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.

 

The car's got 70K so I guess it's time for cleaning the maf sensor as per your suggestion. Thanks for the tip!!

 

isn't that called engine breaking when the rpm go up when you hit the brakes hard? i thought i saw this in the gs forum a while ago.

 

I have the same problem and actually it happened a couple of times. It's when I am driving at like 45mph and then come to a stop light and to a complete stop the rpm drops below 500 and then comes back up.