For those of you with early cars (mine is SN 9116) there are some things to be aware of if your FI is misbehaving. I won't get into why or why not carbs are an alternative...I'll assume that you have decided to keep the car original.
There is excellent material on the rennlist site in regard to 914 FI throttle position switch such as this link: (http://members.rennlist.com/pbanders/DJetParts.htm#Throttle%20Switch). It will tell you much about a number of FI components including this switch, which sits under the throttle butterfly (and is a bitch to get out and worse to get back in). There is also an article on Pelican's site telling you how to set the switch up (http://www.pelicanparts.com/techarticles/914_cooley/throttle_position_calibrate_17-18.jpg). You may also think you can get a replacement circuit board for the switch (only used switches are likely to be found, though I managed to get what may well be the last NOS one in the world recently. The boards are available through SierraMadre and AutoAtlnata, though they are all likely the ones produced by Dave Sprinkle as noted elsewhere on this site. Here's the rub: they are incorrect for the 1970-71 cars and WILL NOT WORK for these. At preseent you won't know that from the SierraMadre web site though I am working with them to get that changed. You only find out when you get the part and see that warning on the instructions. In addition, I am un certain whether the tehcnique on the Pelican site noted above is correct for the early version. Note also that it does indeed have a different part number as listed on the rennlist site. That pages shows five contacts but the 1970-71 cars only have four. I have used the Pelican instructions and they seem to have worked OK...or at least did not make things worse.
So if you can't find a new switch (or can't manage the large $ to buy one) what can you do? Used ones are available from various sources, but I have not seen anyone saying they would guarntee the condition-you might therefore wind up with one as bad or worse that yours. You can try cleaning the circuits on the board by removing the cover and polishing the circuits with a soft pencil eraser. Just make sure you get all the residue out before putting the cover back on. If the circuits are really worn (usually right where your car normally wants to run-at about 3000 RPM) I was thinking of looking into electrically conductive paint to restore the surface of the circuits. If anyone tries this and is successful let me know.
I plan to pop the cover on my old one and see if either of these suggestions will work to "restore" it. Meantime the car does run better (less bucking at low, steady revs such as feather throttle during downhill runs) but I still have a problem with it balking at around 3 grand. Not sure where to head next with that. To solve other problems I have replaced the aux air valve (with a good, tested used one) and the pressure regulator (rebuilt-and an even bigger bitch to get out and back in than the throttle position switch). The injectors are new or rebuilt, the ignition points are new, the timing has not moved. The replacement FI trigger points were defective and only firing two cylinders so we put back the original ones which looked ok.
Anyone reading this who has any ideas? Let me know.
Marty

Marty, you're correct that I never manufactured the early 1.7 boards. However, 914rubber.com just put them into production. Here is the link:
http://shop.914rubber.com/Throttle-Positio...m?categoryId=-1

Oh man, do I wish I had been smart enough to contact you earlier! I don't even want to think about how many of these boards I could have bought for the price of the NOS full switch.
Oh well...any thoughts about the fact that the new switch did not totally eliminate the problem? It developed suddenly so something must have let go that was working up till then. I can play around with the pedal pressure and sort of push through it and once past the car pulls like a locomotive, but sometimes it just feels like it's either not getting spark or not getting fuel.
I'm now past my pay grade on this (which is zero when it comes to FI)

The Djet system has two main points of failure, the TPS and the MPS. Both can have similar symptoms. If you've got a brand-new NOS switch, and still have problems, I would recommend checking the MPS. It has an internal diaphragm that cracks and leaks and then the car runs poorly.