Hi all I am a newbie here so please bear with me
I am having the same problem that a lot of people seem to have, my JGC wont start

It all started a few days ago when my uncle said he had noticed that there were some sparks coming from under the engine when starting (what that doesn't sound normal) I tried to source the prob with my bro but couldn't find anything. Now a few days on the car took a lot longer to start up (usually within a couple of seconds, now about 15-20secs) so I thought I would try to start the car when it is warmed up, this time it struggled to start, idled very irratic and when I touched the gas just died, it did this a few times and now it won't start at all
I have read quite a few posts saying that it could be the crankshaft position sensor, but I checked the car for fault codes and all it comes back with is code 55 (end of codes) None of the posts I have read say wether or not you will always get a code when this sensor fails, or this could be the problem but no fault code is created, any ideas??
Just a few extra points for you,
1)Since I have had the car (about 2 months) there is an intermitant problem with the drivers door lock, it won't always lock on the first push of the remote button,
2)A few days before the starting problem I tried to open the car with the remote and it wouldn't (thought it was a flat battery in the fob) so opened up with the key, alarm went off and couldn't shut it off with the fob. The fob works fine now, the battery doesn't seem to be flat!
Would these problems contribute to a no start situation??
The car is under warranty but the garage will not pay for diagnosis or replacement sensors, I think electricals is quite a grey area when it comes to warranties. As the car won't even start now I can't get it to them to get it checked out, I havn't got any breakdown cover because I thought I was buying a sound motor
Sorry if I have bored you with all this info, im just hoping someone out there can point me in the right direction.
Cheers in advance for any replies
Tim
P.S mine is a 1996 grand cherokee 4.0l straight6 4x4 with 56,000miles