I just bought a 2004 dodge Durango with 230000 miles and it had been sitting for 3 years it had a broken lifter so we replaced all 4 we got it home it was working ok with a few minor issues but then it started to rough idle in park about 500 rpm and the whole thing shakes. so we got recommended to put 91 gas and sea foam in it to clear up dirty gas we have changed all the fluids except for power of steering but the whole thing sill shakes. it also has a hard time getting up to speed and going up hills. what should i do im stuck.
Never use Seafoam in a car or truck engine, it is designed for use in 2-stroke outboard motors.
If that vehicle was sitting for 3 years unused with ethanol-laced gasoline in it then fuel system components (filter, pump, injectors) could well be plugged up and will need to be cleaned or replaced.
Other than that, how old are spark plugs, fuel filter, air filter? Has the engine been checked for vacuum leaks? Has it been scanned for codes and data?
Run a couple of bottles of Techron through it and give it the Italian Tune Up. Hopefully, that will clean it out.
