For starters I'm not a car expert so bear with me here.... I have 1999 Grand Caravan Sport with a 3.3. It has always shifted kind of hard into 4th but is getting worse. Then it started burning the front middle spark plug(not sure what # that is.) I would replace it and it would run fine for a few months then do it again. It also eats 1qt. of oil a week in that same piston(?) My mechanic replaced all spark plugs and wires, tore the engine down, and replaced the piston. Ran great for 8 months then it started again yesterday. I replaced the spark plug but it didn't help this time and it keeps getting worse. It feels like its constantly misfiring. It runs VERY rough. He says he has never seen this before and doesn't know what else to do. Please help! I'm at a stand still until it's fixed.
I have noticed that if I run the a/c or idle for too long it starts running rough.

I don't know what to do besides find a new van and that's not really in my cards right now.

Thank you for listening!

 

Oil could also be coming from the valve guide. Sometimes they fall and the seal comes loose. Some just wear out.

 

When my 99 Sport became a $2150 Strut rust repair job I traded it in for $1200 for a better 2005 SXT with dvd and tow package. At 126, 767 miles it cost me around $5500 total.

It's better to move on to a 4th gen, and get rid of your junk Sport.