My 98 integra is acting strange ever since I took the chipped obd1 ecu out of it and switched it back to the stock obd2 ls ecu its reving up and down really fast between 2000 and 2500 rpms at idel its fast it sounds like im hitting a rev limiter at idel it doesn't do it all the time it does it after I drive it for a little while I also noticed when its doing that and I drive it I could be driving down the road in like third gear and take my foot off the gas and it idels down fast it nose dives like im hitting the brake I don't know what the hell is wrong with it this sucks can someone help me out please thanks