I know I am new to the forum, but I am not new to forums. I don't own a blazer, but one got dropped off in my lap that "just needed a tune-up". It will idle fine, and drive/accelerate fine till it gets some heat in it. If you sand in front of it and hold the throttle half way the engine surges. The idle is still fine. If you try and drive it, it has no power. It will pop through the intake occasionally which tells me it is running lean. The only code supports this.

1995 GMC Jimmy 132k
no ecu on the coolant bottle
fuel pressure good, hold pressure
new cap rotor wires plugs
no vacuum leaks (18 on the gauge)
gutted cat
new o2 sensor
removed the egr and it moves freely
unplug the map sensor and it dies
tps has smooth transition
code 44 lean exhaust

Any help would be greatly appreciated. Thanks!!

 

I replaced the fuel filter and checked the dist. for play side to side and up and down. Unplugged the knock sensor to see if it was too sensitive and pulling back the timing. Still runs good cold and not so good warm.

 

Hello and welcome !

I see You've checked all or most of the usual suspects , and given enough information for a working solution ... OK - no underhood PCM means the unit is inside the vehicle passenger side, glove box area , and Your vehicle is not OBD2 , more of 1.5 . So have You checked Your base ignition timing ? You must unplug a lead going to the computer from distributor (single wire with quick-disconnect) on harness under glovebox to put in bypass mode , then timing light on #1 plug wire to set ignition to 0 degrees . Once set plug back in bypass wire and clear any trouble codes ...

 

No I have not tried that but I will today. Thank you!