Hi everyone i'm a new guy on here, I just picked up a 2000 s10 blazer with a blown motor, I have no other history on this truck.. We changed out the engine and it starts and runs fine. when i try to move it it bucks and cuts out and wants to die(only sometimes others it runs fine), different lights come on in the dash (abs,service engine soon,security light,battery) put it back in park and it revs fine. if i take it out on the road and stick my foot in it, it bucks and stumbles in first gear up until it shifts in to 2nd gear then it goes great no more bucking, also it don't seam to buck or cut out while backing up a hill..???fuel pump? ignition switch? any help would be great

Also the body (2000)has approx. 192xxx, and the motor(1998) has approx. 144xxx miles on it..

 

some codes? how about all the fun grounds on the passanger side head by the firewall? battery connections?

 

oh yeah, u got the distributor in right?

 

had codes checked today. it had a code for intermittent cranks sensor signal..they cleared it, i topped off the the gas tank with 12.5 gallons and the problems is still there but not as bad..also the part i dont understand is it only acts up in forward gears, in reverse it runs great...?

 

could of dinged the sensor or pulled/pinched a wire take a look... its only plastic