Please help me!

My van has been acting really funny…it will want to die at an intersection and will either want to die on the road or begin to rev up as I drive. It also will drop speed and want to only go 25-45 mph. We had it in the shop and they replaced the fuel filter and spark plug(s) and it ran like a dream for a few days. Then it began to not run well again. It seems like it may get worse after it rains. Any suggestions on what it could be?

Maybe they did not go far enough; your fuel PUMP could be on its last legs. They cost more to replace than the filter. Your air filter should also be replaced if it has not already been done. There may be other problems as well.

If your current mechanic is puzzled, find another one since just replacing parts without really knowing what you’re doing is expensive.

My thinking is along the same lines as Docnick’s.
Have the fuel pump’s output checked by your mechanic.

The Mass Air Flow Sensor (MAF) is another possibility.

What year is your van, and how many miles does it have on its odometer? Unless you tell us, we’re just guessing.

Sorry about that…it is a 2002 with 128,000 miles.

This type of serious performance issues should not be possible without a Check Engine Light (CEL) being on.

We have had it checked at auto parts stores and diagnostic testing at the shop and nothing shows up as a problem!!