97 jetta gl only starts when pushed

My son has a 97 gl with the 2.0l engine, it started and ran fine then one day it wouldn't start using the starter. When the car is pushed it starts right up, idles and runs great, but will not start normaly, it cranks over normal and the battery has good power. I've changed the coil, plugs, wires, cap and rotor and added some B&G 44K to the fuel. I can let it run and get it up to normal running temp and shut it off and it will not fire up using the starter, when I try to start it, it sounds like it isn't getting any spark. I am at my wits end, any ideas?

The older Jettas had a starting relay, whose purpose was to turn on the starter when the key was twisted to 'start' AND to shut off other electrical loads, so the battery was turning the starter, but not running the defroster grid or headlamps, etc. I would suppose the newer Jettas have a similar relay. If it goes bad, the car may not be getting the needed signal to the injectors - when the key is in the 'start position. My 90 Jetta wont start using the ignition key, but will when I jumper a wire to the starter. Once running it does fine.
So see if there is a 'starter relay' and check the wires to whatever block that starter relay is connected to. I had the wires come un-connected from the relay block. Just had to push them back on.

Thanks for giving me a some insight, I did check the X connect relay and it is working, I also checked the engine speed sensor which is putting out 2.75 volts. I am not getting anything from my coil until I push start the car, then everything works fine.

Then I would check that the battery ground connections are intact. There are more than one of them. The main cable runs to the block I believe, but there are also grounds to the body & likely to the computer as well. When the starter is drawing a couple of hundred amps, it may result in the case of the coil (or even the case of the distributor if it has one) not being at 'zero' volts. When the car is pushed to be started, this heavy current draw is of course not a factor.
As I said, my Jetta is a 90. The 97's may have used an 'igniter', a module separate from the coil and from the PCM. They need to be carefully grounded also; i.e. to be at the same voltage level as the negative side of the battery.
I have never been impressed with the battery connections on Jettas.