Link Belt 330 Problem

2008 330 lx 6200 hrs bought used, run very well until now . started bogging down other day . Will do it with any function, stick in/out, travel ect. Will run down rpm about 500 below whatever rpm you are currently running. machine does not die, but comes back up to operating rpm. Does this in all three manual work modes as well as auto idle mode. at same time this started happening, computer started flashing electrical problem . diagnostic screen showed E0087 and E0488. Its got after market grip on it, w a trigger to idle up, or down > Have had no problems w it working > When problem started, I idled down using trigger like I always do, because I wanted to check the fuel filters. The primary filter looked dirty, so hopped back in cab, use trigger to idle up, and it came back up very slow, and blowing lots of white smoke. Walked it about 200 yards, bogging down to tops of the hill. Pulled primary filter, and was dirty, and looked to have decent amout of water in it. Got new filters in now Cranked up well Ran for about 10 minutes in auto-warmup mode. Diagnostic screen was clear during this time. I didn't clear it manually, because I have no idea how, it did it on its own. As soon as auto-warm up was over, electrical problem came up w alarm. Diagnostic screen now showing E0087 again machine blowing lots white smoke again . But now, the engine wont get above 1100 rpms in any work mode, the idle speed is constant at 895 in all three modes. The only thing I touched was the filters..... Air filter is reasonably new. Motor sounds and feels smoothwhile running Any help is appreciated

Link Belt 330 Problem