distributor cap where is it in a 99 gmc sonoma extended pickup

That depends on what engine you have since there is no 2.0 as you posted. If you have the 4.3 V6, the cap is at the back of the engine. If you have the 2.2 4 cylinder, it doesn't have one. It's a DIS system.

Thanks, Wrenchtec for answer to distributor cap in a 99 gmc sonoma. What is a dis system? Thanks again.

Direst Ignition system

what could be the problem when you reach 35 miles per hour truck begins to vibrate with accelloration like a wire is shorted out or plugs fouled out? Thanks

Yes, it could be either of those or even a bad coil.

Where is the coil located, we appreciate your input.

There are 2 coils and they are on the back of the engine. all you have to do is follow the plug wires.