My brother has a 98 GMC shortwide with a 350 in it. Lately he's been having trouble with it. When he accelerates, it runs very rough. I thought it needed ...

My brother has a 98 GMC shortwide with a 350 in it. Lately he's been having trouble with it. When he accelerates, it runs very rough. I thought it needed new plugs and wires. That fixed it... for a couple days, then the same problem came back. He took it up to my uncle, who usually helps us with our vehicles, and he put one new wire on and it's fixed.. for another couple days, now the problem's back. I'm thinking maybe distributor? Maybe ignition coil? I'm really not sure, so any help is greatly appreciated.

Are the wires away from the exhaust manifold? If they get too close they will burn out in no time.

You could try a MAF cleaning, that only costs about 5 bucks for a can of MAF cleaner at autozone. The cap and rotor might be something to check. My mom 5.7 tahoe ran rough for a few days then wouldnt start one day. Ended up being the dist. cap, it got so crapped up in there that it wasnt passing on the spark.

Yeah. They look like they're in a good spot to me. I'll check em tomorrow just to be sure. Even the old ones we took off looked fine on the outside. I just figured we'd replace em to be sure. We cleaned the MAF too that day. We'll have to check the cap and rotor tomorrow.

The cap has two torx T22 (i think thats the size) screws holding it in. Be careful not to drop them. You just have to write down where all the wires go. Then take the cap off and if its an old cap it will probly have a thick layer of white crap all over the little metal point things in there, scrap that stuff off and clean the metal up nice and reinstall. If that fixes it then you should probly buy a brand new cap and rotor. Or you could just buy them anyway to replace while everything is off.

Thanks yall for your help. I'll post results whenever we get around to workin on it.

Well we got the cap off yesterday and cleaned the little contact points. It's still doing the same thing. Anymore ideas? A new cap will probably be next on things to try. It definitely can't hurt haha

Replace the rotor button at the same time as the cap.

Thanks. Once again I'll post an update once we work on it.

Just got done puttin a new cap and rotor on. Time to go grab an ignition coil. We're also going to replace the #2 plug. That's where the miss is happening, and the plug is already fouled.