Recently purchased this vehicle in order to sell it on my small used car lot. When it was delivered, the battery was dead so I jumped it and proceed to take it around the block. When I finally got to a spot I could accelerate, basically nothing once I got to 20mph other than a very slow climb in mph. Got it back to the lot. Had to run across town to get my "primitive" code reader. While I was gone, my partner said let's disconnect the battery while you're gone.(maybe battery went out mid-cycle and prior owners didn't keep battery charged) I get back, write down the codes, decide to give it a try....drove fine. Today, I go buy a new battery, hook it up, no go...back to little acceleration. Took it to a guy I know that has a non-primitive reader, he did his thing, drove it, no change. Said he'd do some research. But, when I get in it to expectedly "limp" the short distance to the lot, it drives fine....I drive it for about 30 minutes. Stop to go in a store, come out to get going to find it limping again. When in park, the tac will rev. I noticed each time it didn't run properly, it seemed to go in reverse hard. When it ran fine, it didn't do that. Any thoughts? I just need to make sure this vehicle is safe for anyone who buys it without potential taking it somewhere and let them throw different ideas at it and potentially throwing away any profit I potentially have with it. Regardless, the safety is the main priority.