FC3S S4 TII barely gets to 3k RPM

[rtj_wpg]

Hello everyone,

I have been battling with this issue for over a week now.  I was driving my FC3S S4 TII along and it was boosting fine and performing great.  I stopped at a red light and all of a sudden my car could barely go up to 3000 RPM and the sound of the exhaust was a lot different.  With the hood popped and it idling you couldn\'t tell anything was wrong as the motor has zero shake.  When I step on the gas the RPM\'s go up very slow and non rotary like.

I have changed plugs, plug wires, done a compression test and compression is good, tested fuel pump and am getting 40PSI to the motor, I tested ignition coils and all four plugs are getting solid spark and I checked to make sure my AMF is connected tightly.  My vacuum is at about 12 in. solid.

I\'m kind of at a loss because all the forums say I have to change my fuel sock and there\'s issues with my fuel pump but I\'ve checked all that and all is good with fuel supply.

Any help would be greatly appreciated.

Thanks,

Ryan

[BlitzBoy]

MAF sensor could have gone faulty is my guess.

[Prof]

+1 on that, the Series 4 Turbo II motors had the flapper rather than the cone, and the flapper is a lot more complex internally with resistors and a wiper that swings across the contacts.  It might just need a bit of switch cleaner squirting in there and move the flap back and forward, - I think you can unscrew the cap on it to get to the tracks.  I also think it gets a 12v feed (the Series 5 cars only use the 5V reference), so check you haven\'t had a fuse blow that might be cutting the 12v to it.
 
It could be limp mode, but on the S4 there\'s no electric OMP, so the most likey thing to put the car in limp mode is the AFM.

[rtj_wpg]

I have replaced the AFM with a known working one and that didn\'t work either.  The fuse that you mentioned, where is that located?