Hey, this will help with your sludge! : buy 2 bottles of oil. a bottle of cheap crap. and a bottle of your normal oil, : a bottle of engine flush : 2 oil filters. perform 2 oil changes. drain the oil when its warm, its runnier and will empty your motor out better. put in the cheap oil and the engine flush, had the filter, run it for 15 minutes. drain that out when it warm. put in the good oil and filter. you might have to flush it a few times with cheap oil if you need to, you want to clean the inside of your motor.. much cheaper than a mechanic's opinion. now check your pcv valve, if this is clogged it will cause your engine to sludge and rob performance. on your valve cover there will be a hose attached to it. pull the hose off and undo the pcv ( has a barb )usually a 22 mm or similar its a one way valve so it is designed to only let pressure out , not in, they are quite cheap. repco should sell them.