Carb or Ignition issue?

I have this issue that has started recently.

My truck is a manual 89 B2200 Carb.

The truck seems to be bucking and popping when accelerating. It almost sounds like it is starving for gas and is low on power. I have already replaced fuel filter and fuel pump. I checked for vacuum leaks and have yet to find one. It started just randomly one day on my way home from work. It is still driveable but I want to get this fixed prior to making my trip up to Tennessee.

I thought about checking my pre-cat as I noticed exhaust (very small) smoke when revving it up while not moving.
Also I noticed when I replaced fuel filter is seemed like it never fills up (not sure if this is suppose to be like this) which is why i replaced fuel pump.
Any pointers to check.

Hey Wrench,

Is this a stock truck or do you have a weber carb?

Dan

It is the stock Niki Carb.

Bump,

Any suggestions?

Check all of your ignition components, spark plug wires, distributor cap & rotor, spark plugs, if in doubt, replace them, they are cheap and easy to replace.

I had a bad wire on a GM car I had, when I accelerated, it would arc across the cap to the head, making that cylinder dead under acceleration, while cruising and idle, it ran fine, upon fine inspection, the spark plug boot had a crack that was only visible when I flexed the boot. Spark is stronger under acceleration, and it takes more power to arc across the spark plug, so that is when weak ignition components show.

I will have to check those. I replaced them (wires, cap, rotor and plugs) a little less than a year ago. Perhaps one of them got damaged.

I will add something I learned and or just did not think on with a similar issue.Check the coil.I use a accel coil (universal one) sold at most stores,and use same brand 8 mm wires and ngk plugs soley.Yes you would have to buy a v8 set of accel wires but,you end up with 2 sets and really low cost for the much better general auto crap wires sold everywhere.The only other wires I trust are the napa brand which hold up pretty good.Just a idea to share.

87forever

Do you have part numbers or links to the parts you are talking about so I know which ones you recommend and can compare prices?

Thanks in advance!

You have ruled out oil seal in the distributor being bad, allowing oil film to coat the cap interior?

Wrench funny you brought this up. I just finished fixing what started out as the same issue as you. 87 B2200 syaryed out of the blue acting like yours. Changed fuel filter, fuel pump, changed to weber carb, put on pacesetter headers. Anyway all that did nothing. Same problem. Changed coil, plugs, wires, distributor cap, rotor button, and still had issues. The problem will more than likely get worse. What we finally found was the ignition module on the distributor was only completeing it's circuit intermittently. When we checked for spark previously we would see it but the truck would misfire and sputterr etc. Finally she gave out completely and stopped giving us a spark. Voltage was good at the coil. Still no spark so it had to be ignition module. I went ahead and replaced the distributor because of the age but the ignition module was the problem. Changed the distributor and she fired right up. Good luck.