Diagnostic Code 51 for a 1994 Plymouth Voyager is the vehicle running too rich or too lean on fuel. Diagnostic Code 35 has to do with the cooling fan for the engine. It is not coming on at the proper times due to a short or a bad fuse.
The transmission computer defaults to second gear when it detects a fault and sets a trouble code
The door being open.
The thermostat may be installed backwards
Low brake fluid and the parking brake being on are the two most common causes.
There must be a short in the system somewhere that causes the fuse to blow.
One cause why a Plymouth Voyager sputters is because the driver may be holding the gear shift button, unnecessary for going through drives 1 to 4. The gear shift button is a safety feature that keeps from reversing while driving.
Trouble code P1470 means: Leakage Diagnostic Pump Control Circuit Electrical
It is possible that all the vehicle needs is a tune up. One of the most common problems with a vehicle that will not start is a clogged fuel filter.
Transmission code present. You need to check the TCM for codes to know possible causes.
Trouble code P2146 means: Fuel Injector Group "A" Supply Voltage Circuit/Open
The only ways to improve mileage are to check tire pressures, replace spark plugs, replace air filter, repair any causes for the check engine light to be on.....
As there are a few causes of knocking in an engine, it is best to take it to a qualified mechanic for repair. Typical cause is a damaged internal part. Depending on the damage, it may be cheaper to replace the engine than it is to repair it.