Ignition Problem?

[Denis]

Have a '68 W-300 with a 318 LA engine. When I bought it the distributor was worn out; so I got an Dodge electronic distributor from a junk yard and installed it along with Crane MSD module and a MSD Blaster hi-energy coil and new plug wires and removed the ballast resistor. That was 5 or 6 years ago and truck ran great, no problems what-so-ever until February. Wouldn't start. The MSD module and the pickup unit inside the distributor we both bad; so replaced the pickup with a spare out of another distributor I had and changed the module over to a GM HEI unit. Truck now starts easy and runs fine at any speed without a load. However, there is an bad engine miss when ever the engine is placed under a heavy load like going up a hill or hard acceleration. Have changed the plugs but still have the problem. Any ideas as to what the problem could be?? Is this a symtpom of a weak coil or weak pickup unit. I hate to start buying parts by trial and error if I don't have to.

[Kevin Mienke]

I am thinking that you may have a fuel delivery problem when your truck is under load and at maximum fuel demand.

Blocked fuel lines or pickup tube could cause a hesitation under maximum fuel demand conditions like driving under a load uphill. Your fuel pump could also be suspect.

Unfortunately, you will probably have to go through a process of elimination to find out. Since you have already replaced the plugs, and your experience leads you to believe it is an ignition problem, I would continue to follow the ignition checklist, starting with the dist. cap and coil as either could be at the root of such a problem and neither is extremely costly or time consuming to replace.
If your ignition checks out and you are still not out of the woods, I would begin to look at your fuel system.

[Denis]

Ignition Problems

I hate these types of problems. Truck was running fine, now it seems to have developed multiple problems all of a sudden. That is my plan to replace the coil, then try another distributor. If that fails to correct the problem, I'll have to look at the fuel system.