I’m new to the K5 Blazer world and this is my first post so bear with me. I've searched this site a little bit but I haven't been able to find help for my problem.
My 84 Blazer has been having some issues accelerating. The problem doesn’t start until about 30 mph when I’m accelerating at a normal, steady rate. At this point the engine begins to sputter. If I begin to accelerate faster or stop accelerating all together the sputtering usually stops. The engine also sputters if I try to maintain speed up an incline. I just recently bought the truck so I’m not sure when any of the parts have been replaced. I’m going to replace the fuel filter today but unless it’s clogged I’m not sure where to go from there. Has anyone else had a similar problem?
Thanks for your time.

 

I changed the fuel filter but my problem still exists. The old filter didn't appear to be clogged. Some additional information I left out of my original post may be helpful. The sputtering problem only occurs when the engine is under a load. If I'm in park and rev the engine everything sounds normal. I found in some other posts that this could be due to a timing issue but I'm not 100% sure on what that means. Also, I think the engine is running rich as the exhaust smells like unburnt fuel. Could these problems be related?

 

I'm not an engine guru but here's what I would do. Could either be that the timing is off or one or more of the cylinders is dead. I'd start with the easy/cheap things and go from there. Start pulling the plugs one at a time, you want to keep track of which cylinder they came out of. Check to see if they are wet with gas, fouled with carbon, or just worn out and need to be replaced. If you notice just one or a couple smell like gas then the problem may be farther back like the plug wires, cap/rotor, etc. You can also check for spark on the plug but be careful. With the plug out and the plug wire connected, ground the threads on the plug by touching it to something metal and see if there's a good strong spark (hold by plug wire well away from the plug and wear a leather glove to be safe). If just one plug is bad it's either a bad plug or wire. More than that and I would suspect the cap/rotor. That's just to diagnose what's wrong. But if you're going to be pulling plugs/wires/cap/rotor any way, why not just replace them while you're there. They probably need it along with the air filter. If all seems good, then you'll need to check the timing with a timing gun. Not sure how to set the timing on an 84 or if it's computer controlled but check the other stuff first and we'll go from there. Worst case I can think of is that the timing chain has stretched and and jumped on the sprocket which means pulling the timing chain cover and replacing the chain.

 

check your vacuum advance too. basically pull of your distributor cap and disconnect the vacuum line off the carb coming off the distributor and either use a vacuum pump or your mouth to suck the air out of it. it should move and hold there if its not moving or leaks down it needs to be replaced

 

i replacded my egr valve and rebuilt my carb fixed it dont know which one did it though