1985 S10 Blazer
2.5 Standard trans.
4,000 miles on rebuilt engine

Engine starts up fine, at 1st at higher RPMs as normal
Shortly later it idles down
Takes off OK as you shift to 3rd and sometimes as late as 4th gear the engine just stubles
push gas to floor no help
let up and it will try to run
dwn shift andengine still no power.

NEW PARTS
TPS
O2 Sensor
MAP Sensor[/align]Coolant Sensor
Fuel pump and sock
Fuel pump
Fuel Pump relay
Distributor cap and Rotor
Plugs and plug wires
Carb. changed out from a different 2.5 that was runing ok
Coil changed out from a " " "" " " "

Votage input and output checked and OK on:
TPS
Map
O2
Alternator voltage is 15
EGR working OK

Field Service Mode--shows to be in closed loop
No check engine light after start up
No codes stored in ECM

Timing 8degreesat idle after warm up--shows advancement

Fuel pressure of 11 PSI with engine runing


Today I am going to check the wiring to the ECM and make sure the various signals are reaching itbut I'm sure they are because if you disconnect the TPA, or MAP or O2 sensor you will get a check engine light and a code. Going to also checkforpossible vacuum leak.[/align][/align]If anyone can think of what else I can check please let me know. I've tried a local garage and was soaked for$300. for troubleshooting only to be told it MAY be a fuel problem.I've about had it!! Im begin to thank a gal of gas and a match might be the answer but then again gas cost too much.This is my Grandsons car I got for him and put the new engine and also painted. If I don't solve the problem soon I am going to find a different intake and put and standard carburator and distributor in it. Agin thanks for reading and any help you may have.
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When you rebuilt the motor did you get a new distributor? How many miles are on it?I am wondering if its failing at higher RPM's?Does the ECM have the heat sink gel on the bottom of it? Just throwing that out there.