if it doesnt shift into gears smoothly or at all. rev. is the first to go in most cases.
Bad fuel filter
There are several reasons why a check engine light would constantly stay on a 1999 Plymouth Neon. There could be a bad valve, a bad sensor, or even a bad fuel pump. The only way to know the exact reason is to have the car checked out.
The belt tensioner is probably bad.
Yes
Bad clutch? Bad transmission? Worn synchronizer?
You will not know and you cannot tell by looking at it. This is why it is mandatory that you change it every 110,000 miles. Warning: This is an interference engine, so if the belt breaks you will have serious engine damage.
im guessing a bad idle valve
bad pump defect in pump
The tranny cooler inside the radiator went bad.
Mine was vibrating due to the Motor Mounts went bad . check BOTH simple fix About 125.00 for both.
My experience with this in my 95 Plymouth neon is that it was a fuel pump going bad. Replaced it and the fuel filter and no more problems.
A Dodge Neon may experience shaking during acceleration due to bad spark plugs, incorrect ignition timing, or a failing transmission. Shaking can also occur from worn motor or transmission mounts.