electrical B.S. Any ideas anyone?

to make a long story short, i have a 97 S10 blazer, 4.3, i replaced the motor with the same one from a 2001, but ever since then i have been having problems. some times it will run, sometimes it wont. i just discovered that there was gas in my oil, about a quart of it. I talked to a guy at the dealer and i came up with 2 conclusions. i know that my injectors, hoses and regulator, and all that good stuff aren't leaking cause i tested them. the guy from the dealer thinks it has something to do with the sensors being different on the 2001 motor, but i thought they were all the same, maybe i was wrong, the ones that were different, i changed, like the knock sensor on the back of the block, and one other one i couldn't tell you what it is. the motor has a distributor, but the timing is regulated by the sensors throughout the motor, so one thing i was thinking is that the timing could be off, because it won't start, and it doesnt sound right when it cranks. so i was thinking that maybe the injectors are dumping feul in at the wrong time, and the gas is just leaking right past the piston rings because there is too much of it, or, that if I would just switch right back to the 97 throttle body, which fits perfectly, the injectors would be working right. anyone with any input i would really appreciate it, i love my truck, but im ready to burn the darn thing, i cant figure this out for the life of me. Thanks!

If you had pulled the distribibutor and put it back, you may be 1 tooth off... The 2001 like the 99 is a locked distributor... There really isn't any real difference in the motors themselves. Being 1 tooth off will cause your condition... Every time I pull one of those damn locked distributors I always end up being 1 tooth off and it runs like ass or doesn't run at all...Usually takes me about 3 or 4 times to get it right.