I have a 1997 jeep wrangler 4 cylinder that has trouble starting on occasions. It will crank and crank but never turn over on the first time (this will happen probably like 75% of the time). And then after this it will always fire on the second try. On the other 25% it will start with no problems. I have tried to pump the gas a little and that seems to help and it will start the fisrt time like 50% of the time. This all does change a little day to day (I think its bi-polar). Please, any help is appriciated. It has about 150000 Miles it and it does have a leaking exhaust manifold if this makes a difference.