2 weeks ago, I had a hi flow cat installed, changed my oil, o2 sensor and shocks.The mechanic didnt hook the air pump back up, either.Truck has been running like a champ. Suddenly, today, she starts running crappy like she was months ago. I have an erradic idle, sometimes around 800, like usual when in gear and on the brake, sometimes as high as 1300 in gear on the brake. When I go to take off, if I give it a small amount of gas, she jumps and jerks. If I floor it, she seems to do ok. My temp gauge has been reading a little hotter than usual, as does my voltmeter. My milage was down to like 8 2 weeks ago, and since I replaced the o2 sensor, seems to be better(like 10). I was thinking EGR valve, but 2 mechanics I talked to, said they've never seen 'em go bad. One mechanic is young, the other is very good at what he does and probably has 25-35 years experience. Any help would be greatly appreciated. I love the bronco, but a year of trying to troubleshoot these various probs is getting old.