Chugging in Gear

We have a Ford Windstar with a 3.8L V6 2001. Got it from a dealership 4 months ago. It stalled the first time I started it after paying for it, but then it started right up and was fine. It was fine for a long time but now has other issues.

Once started, the engine revs high for about 15 seconds, then slows down. When sitting idling, the engine is running rough, and the tach bounces between 1000 and 1500. It stalls after running for a couple of minutes in park while idling quite often.

When put into gear, it starts chugging, like a high/low/high/low kind of surging at regular intervals. When the engine is under load, it's backfiring (light pops, some barely noticeable), and when stopped at a light, it goes back to chugging.

We've changed the feul filter, plugs, and wires, but not sure which avenue to follow here, as we're kind of strapped for cash, and if it isn't the fuel pump, then I don't want to run out and buy one. No check engine light comes on.

If anyone has some insight, I would really really appreciate it. It's been running like this for 2 months now, and has given me some rather uncomfortable moments, so I need to get it fixed.

Thanks for taking the time to read.

You should clean the air intake throttle body inside, and also check for a pulled off vacuum hose, or vacuum leak on the engine.There are many posts on this forum giving details of the procedures.

very good!

Thank you. I did find one hose not hooked up and it runs better now. It still does the same things, just not as bad as it was. Guess I'll try to hunt down more vac leaks then. Thanks so much.

A bottle of Techron injector cleaner in the fuel tank may also clean up the fuel injectors, and fuel system