Well, after a lot of time trying to solve my problem I think I've narrowed it down. When it rains or there is a lot of moisture in the air my 99 2 door four wheel drive kind of jumps forward while while accelerating, or if I keep it at a constant speed. It did this when it was out of time, and after searching for vacuum leaks.. I think I may have narrowed it to the distributor cap or wires. I'm thinking moisture is getting into the cap. My friend told me his dads dodge had the same problem when his was getting moisture in the cap. So could that be a possibility? I don't have a delco cap/rotor.. but it only does it in the rain, or morning with a lot of moisture around. Would it be OK to put some rtv silicone around the cap where it bolts down to seal it? Now, km not experienced with mechanics, I'm 17 and learning. So that is why I come to you guys..

 

I'd try the distributor cap. If they crack and water gets in it'll make it miss. Possibly wires never had wires do it but I've had distributor caps do it a lot. Check the rotor button for corrosion while you have it off. Cheap fix if its that

 

Cap, rotor and wires are the most likely cause. These engines are pretty fussy, use AC Delco cap & rotor and any good quality wire set. Put a dab of silicone dielectric grease on each terminal, inside and out, of the cap. While the cap is off, check the vents on the bottom of the distributor. GM had a TSB a while back that intructed to remove them for better ventilation of the cap:

 

thank you guys! I do have a cheap cap/rotor.. which is probably the reason. I have a warranty though. I'm going to go to auto zone and see if I can get my money back and get a delco set. Captain, after doing research on this I have seen you post that a few times. I went out to remove them gesterday , then it started to storm. It'll have to wait till tomorrow most likely

 

Those are text book symptoms of a cracked cap. Do NOT put RTV silicone on the cap. If there are any vapors from the self vulcanizing, they can ignite and your cap can explode. There are other things that can cause it but put a good cap and rotor on.

Try to get a cap and rotor with bronze, brass or copper electrodes. Blue Streak is what I've used in the past to take that last little miss out of an engine. The aluminum electrodes work okay but corrode a lot faster. I don't know if Blue Streak brand is still available but I know the brass electrodes are.

 

Yes moisture can have a huge effect. I used to have an old '95 Altima that I used for work and every time it rained, the same thing happened to me, it would shake really bad or surge while driving. Changed the cap and rotor and it ran like a champ.

 

My 99 Blazer does the same as your swanman, i put on new AC Delco cap, rotor, wires, plugs and it still acts up in damp weather, i dont know what else to do, oh, the vent was open too.

 

Im pretty sure when the ignition coil starts going out they hate moisture also. So that would be something to look into as well if you have done everything else. Generally if you're having issues with moisture secondary ignition is the problem. So my guess is your coil since its the only part you didnt do. Captain will probably tell us for sure tho

 

I put on another duralast crap and rotor and it's driving better for now. I'll get to the wires And a delco cap and rotor in the future. I'll update if conditions change