Where's the plenum and how would I clean it? Kinda learning how to do things on my own. Haha. Also, what's the best performance chip I could put in to help with MPG and horsepower without changing the ecu?

98 ram 1500 318

 

Read the stickied plenum thread at the top. You dont clean it, you replace it.

SCT Hemifever is the best tuner for bang for the buck, chips are usually snake oil that do nothing.