Help! (Second Try)

I’m puzzled.



I have a 2000 Plymouth Grand Voyager with 90K on the 3.0 liter engine. It runs very rough between 40 and 55 miles per hour.



It started running rough and missing, so I took it to my mechanic. We did a tune up, but that didn’t help. He found a leak in the intake manifold, and we fixed that. Still nothing. Code said it was missing on cylinder 2, so we replaced the injector.



The thing still runs like garbage.



Someone mentioned it might be a bad EGR valve, but nothing comes up in the codes. My mechanic says we need to replace all of the injectors, but I have reservations that such a specific problem would be caused by bad injectors. At low speeds (under 40) and high speeds (over 55), and when I’m in passing gear through 40-55 it runs better. Not purring, but not nearly as bad as when I give it normal acceleration between 40 and 55.



Anyone out there have any idea what could be the problem?

What is a “complete tune up”? It should have new spark plugs AND wires. New fuel filter also. Pull #2 spark plug wire and check its spark. Compare it to #3. If it’s noticeably weaker, swap the spark plug wires (#2 with #3). If #2 spark is still weak, check the ignition coil.

I wouldn’t be changing ALL of the injectors if only cyl#2 is misfiring.

Check the coil for that cylinder/plug and wire.

Besides, injectors can be tested without replacing.