Hello. I've had 4173 for 3 years now. She has a stage 2 DMCH crate engine (Automatic) with about a 1000 miles on the engine. About 6 months ago I started having a complete lack of acceleration. When you step on it the revs build very slowly but eventually has no problem getting to 80 on the expressway. I'm talking 0-60 in about 20 seconds. Also when I step on it, the AC switches off until I let off on the accelerator. I have replaced the fuel pump and fuel filter but still the same. When it gets up to temperature it also sometimes idles a little rough. Any ideas?