Porsche Repair: 944 hickup upon hard acceleration, air flow meter, automatic transmition

Question
  Hi, I have an 85 non-turbo 944 five speed. It has been running very well with no problems other than this : on hard acceleration and high rpm, usaully about 5000, a very quick jerk of decceleration followed by a jerk forward occurs. A hickup is the best way I can describe it; it sort of feels like a crappy automatic transmition shifting. I'm not exactly sure what happens after this hickup, as I am usually scared into shifting into the next gear when it happens. It doesn't seem like a likely place for the clutch to slip, (the clutch is also relatively new) so I think its the engine, possibly fuel starvation of some sort? Anyway, I'm no mechanic, so I'll stop speculating. I would really appreciate any thoughts you might have on the matter. Thank you.

Answer
Hi Phillip,

I'm thinking of only one thing.  It's exactly as you have described it...the hiccup.  When it hapened to me I thought it felt like the engine died and as soon as I felt it and the adrealine started flowing the engine felt it restarted...almost as quickly as it had "died".

This happens when the air flow meter (and different mechanics will call this different names) "sticks".  The meter calculates how much air is being sucked into the intake and sends the measurement to the computer.  The meter is actually an opening before the intake that is controlled by a "door".  Sometimes the door opens and closes smoothly...sometimes because of gunk in the way, the door isn't as smooth.  If it were to stick at point A instead of travelling a tiny bit further to point B, less air would be measured and less fuel would be matched with it...likely resulting in a stumble...or a hiccup.

Most mechanics will want to replace the "meter"...sometimes it just needs to be "un-gunked".

Give that a look.

Dave