1997 voyager gauges ?????

Have a 1997 plymouth voyager driving down the road and the gages all go dead the service engine,abs,seatbelt lights come on the van start feeling slugish not shifting properly but driveable. some times after a few miles they will come back up some times after a few days. the engine light will stay on the other lights will go off and it runs fine. engine light goes out maybe after a week or so. now it got to gages working engine light on, cutting out,backfireing in the throttle body, when you step on it, but on flat road seams fine, idles fine. codes i have got from the ignition are 12,43,66,55. took it to auto zone and they said it was a dealer thing. and you now what that spells $$$$. don't have a code book. anybody have any answers.