E:\My Pictures\my truckswapped my 86 out to tbi out of a 1987 that worked fine in donor truck.i changed everything , wiring harness, intake ,fuel lines etc. but now it has a hesatation about quatre to half throttle. no service enging light coming on tried new o2 sensor,new temp sensor cannot figure it out

I see it’s you first post, so welcome to the message board.

Did you remove or move the distributor at all?
Did you set the timing? If you did set the timing did you unplug the set timing connector when you set it?

Check the computer for codes. If you need instructions, let me know.

yes had to use dist out of donor truck and we did set timing with wire unplugged. the only thing that dont work is the oil light the light bulb is good sender was good on donor truck used it cause 86 only had singel wire and 87 had 2 wire connector (one beside dist) one down by oil filter but i dont see connector to go to that one??? (oil sender)

The oil pressure sender should make no difference in this case. Have you verified the fuel pressure is where its suppose to be? You may have a small vacuum leak messing with the system, ie, EGR valve leaking.

thanks for reply. never checked pressure.worked perfect on donor truck 2 days before? unplugged egr valve and plugged off hoses no diff? it seems to work little better when its cold but as it warms up then gets worse.could be still vacume leak. is what im thinking to as it warms up requires less fuel . maby getting to much air then.idk thats just my guess but cannot find leak . frustrating and puzziling??????

thanks for reply. never checked pressure.worked perfect on donor truck 2 days before? Did you transfer the gas tank, fuel pump, and fuel lines from the donor truck.

it seems to work little better when its cold but as it warms up then gets worse. You may want to test the temp sensor, that the ECM uses, on the intake manifold.

Have you checked it for trouble codes yet?

yes used my tank,donor trucks fuel pump,no codes in ecm,and new temp sensor. kinda seems like timing in a way backfires out threw throttle body when half throttle once or twice then take it runs good full throttle????? used lines from donor and new fuel fliter

I would run a compression check to make sure all cylinders are equal and not a head gasket leaking. Also if you pulled the distributor, double check all of your wiring. And recheck the snugness of the TB to the intake. Did you use a new gasket at the base of the throttle body? Also check any vacuum lines to make sure that none are cracked and may be opening up a hair when the engine warms. Then check all wires and hoses at the MAP sensor, etc. Are you sure they are in the right place?

Kevin