2004 XKR, after I cleaned the MAF, I've lost some acceleration under medium, medium hard gas pedal. Prior it accelerated up smoothly, rapidity and kept picking up torque and speed. Now it accelerates, but then pulls back (like it's air gets cut off) and I no longer feel that torque building rapidly. Any thoughts? I never touched the wires, just CRC MAF spray. Have a messed it up?

 

Sure you did not create an air leak ..seated the big clip right or disturbed the breather pipe?

 

Plugged it back in?

 

Seated the big clip? I dont know what that means. I did open the air filter box to inspect air filter which was new, and removed the plastic air intake tube to inspect throttle body whch was fine. That was very easy. Unplug MAF, unscrew retainer ring off filter box and throttle body ends and it pops off. It went back on very easily exactly as it was. With filter out I saw an extra air input door on a solenoid I figured activated under heavy throttle. While wiping the inside of filter box, I touched the very flimsy tip of the spring and it popped out from behind its peg. I reset it the spring and couldn't believe such a flimsy spring on these great vehicles. That's it, nothing has changed.

 

The possibility of a crack appearing in the intake tube is highly possible.
Might be worth taking it off again and view it from the inside up against a bright light.

 

Great idea ty

 

Also, check the air filter box to ensure it is properly sealed and latched. I have always found that is much easier to do when you unscrew the single 10mm bolt holding the air box in place and lift the air box up and out of its installed position....

 

Question, the only seal is lid to housing, correct?

 

Correct....

 

These cars take a LONG time to get used to and work with the signals coming in from different sensors. The info accumulates and the ECU and TCM make adjustments over time. Sometimes a hard reset after making changes to major inputs like CTS, TPS or O2 sensors and stuff can help. The car is probably a little confused and working with the old accumulated info from the dirty MAF? Just a suggestion

 

Thank you i did a full on hard reset. No benefit. How long should i drive after all this? Seems like it should be automatic.

 

Right on. Let me ask. After you did the reset were you able to notice or observe data from the car telling you 'depth' of the reset?

Over these last few years and more than a few resets, and maybe this is just superstition and false beliefs, I do resets a little different than some...

I'll remove battery posts, clip them together, and then turn the key to the ON position in the car. In my mind (and I could be wrong) it puts a lot more (if not all) of the cars systems in the reset circuit, if that makes any sense? This approach seems to give me a deeeeeper reset. Again, there is nothing to confirm this, but it's what I do.

 

Is it possible that you may have damaged the MAF sensor?

 

Exactly what I did, and left it overnight. Not sure what you mean by Depths. I can recollect fuel pressure and MAF readings unchanged. Thanks

 

Thats basically my question. I did nothing but remove and spray thoroughly with CRC MAF cleaner. I repeated days later. No change from second cleaning. I never touched anything except the top and let it air dry much longer than reccomend. Since the only thing that happened between great smooth acceleration and slow pull back then slower acceleration is the cleaning I'm thinking somehow the MAF stopped functioning as well as it was. I've not driven much, maybe I need to drive longer?? I've berm on a 20 minute drive and two shorter drives since.

 

After your re set or any battery disconnection, you must turn on the ignition and move the accelerator to full throttle and back a few times slowly or it does not accelerate right and takes a long time to learn.

 

I did a specific procedure more imvolved, to alert the gearbox to tune to the next 15 minutes of driving. But ill perform your reccomendation as well. Ty