Hello all, I'm Chris and I'm from Roanoke, VA. This is my first post but am not new to the Chevrolet world although I've been on a hiatus for a while due to playing with Hondas. Here's my issue, my father passed away back in 2012 and left me his 1995 Cheyenne which was sitting for probably 2 years before I started using it to pull my aluminum bass boat. It has ran questionably the entire time and I'm just now at a point where I can really finally spend time on it. While driving the truck(305 TBI with 190xxx miles) the engine is sluggish and then clears up and power kicks in hard. I'm banging my head as to what is going on, as I've replace the distributor cap, rotor button, plugs, wires, coil, ignition module, pulled the TBI and cleaned everything and replaced seals and regulator diaphragm, and replaced the fuel filter. I've replaced all of these things with the Hope's of fixing the issue but also thinking it may not and these are good things to change anyways. I'm trying not to dump a ton of money into it since I'm planning a 5.3 swap after I find a donor truck, but also want to continue using the 305 for fishing and normal truck stuff while I'm building the 5.3 on the engine stand. All of these things have helped performance when the engine isnt holding itself back but still hasn't solved the problem. Any help is greatly appreciated!

 

Sounds like a fuel delivery problem. Possibly try to replace the fuel pump. At 190k it might be on the fritz and fail soon. My old girl is starting to do this too. These little 305's are strong running motors, packs a punch for my single cab '88.

 

1995 was the year that some vehicles upgraded to the OBD II diagnostic system and some had the old OBD I system. I agree it might be a fuel delivery issue so a fuel pressure gauge would be handy to use. It should be 9-13 PSI with the TBI system. As far as upgrading the motor, I think it would be easier to put the 350/5.7 motor in your Chevy. The 1995 305/350 use the same mounts, brackets, and exhuast system at the manifolds.
Also the 5.3 lier mill will likely be the MPFI multi-port fuel injection system, so you'd have to modify the fuel pump and regulator to put out 60 PSI for the fuel injection system to work properly, and likely need to upgrade the electronics for the vehicle to run properly unless you were to swap out the fuel injection system back to use the throttle body fuel injection unit on your 1995 305 cubic inch motor. It's likely that might require a modified intake manifold on the 5.3 liter engine.

 

Just FYI the only 95 models that would have had OBD2 were trucks that originally sold in California and maybe a few other strict emission states. Even then I think it would’ve been very late models, so they’re few and far between. Otherwise OBD2 wasn’t required until 1996 (model year - the trucks could’ve been built in 1995 but the model year is what’s looked at for all info).

 

Yeah CA emissions standards are high, but NY and OR are too. Still have my multi-vehicle scan tool for all the pre-1996 vehicles, with all the adapters!

 

Yeah its a joy living in CA....NOT!!! The Smog check is getting stricter and stricter every damm day it seems like.