Truck hesitation

[drillingmachine]

my 89 burb seems to hesitate more now that i put Lucas complete tune up in my gas tank. I have had the plug wires changed, plugs gaped and replaced, fuel filter replaced, rotor cap replaced. It hesitates more when I first use it that day. when it does hesitate I floor it so it can get past it and does pretty well. sometimes i can hear it make a pop sound in under the hood, when this happens. I don't know if this has anything to do with this, but I am down to my last 1/8 tank of gas and has started to hesitate even more. Oh, one more thing, sometimes when at a stop or idle, the idle goes "up and down". I do have a bad battery that I need to change.

Is there a way that the fuel pump can get clogged? could it be bad gas? I have cycled through gas several times over. could it be some kind of spark problem?
I didn't post this in suburbans forum because people hardly look at that forum.

[Mickey_D]

Have you messed with the timing at all?

Do you have a fuel pressure gauge you can check the pressure with? Although being an 89 I would imagine it's TBI, in which case you're going to need the adapter to go in the fuel line if it is.

Have you pulled the air cleaner off and looked at the spray pattern of the injectors?

Any vacuum leaks?