The first leg of my 3000 mile trip went great. 19-20.5 mpg, smooth sailing. After leaving Tuscaloosa for Houston I ran into two issues:

1. When climbing a hill, I suddenly couldn't go over 55. It was still in OD, and the MIL didn't come on. I pulled over, checked my fluids, got back on the highway, and everything was okay. When I got off to fill up, it was sputtering and stalled as I pulled up to the gas pump. These two tanks got me only 16-17 mpg, in similar conditions, and now it is idling very high.

2. The second issue is a strange one. I experienced this problem very briefly about a month ago. When I'm going about 60mph or higher, when I give the van gas it shakes real bad. When I let off the gas, it goes away. It'll do this for awhile, then go right back to normal. I was thinking it may have something to do with the AWD computer, and I was thinking of disconnecting it to see if that makes a difference. If I do disconnect the AWD computer, is it okay to drive like that for extended distances? Is there anything else that may be causing this issue?

Thank you in advance for sharing your Aero knowledge.

 

please pull the ECU codes per the sticky thread at the beginning page of the aero forum and post results here

no use throwing away your money in a guessing game

what work has been done on the engine/tranny in the past year?
how old are the plugs and ign. wires?

is this the 4L auto AWD package?

AWD problems do not manifest themselves as engine performance issues such as low power and missing. you can unplug the AWD controller with no problems caused, it is safe to drive.

 

The two issues did not happen concurrently. I think I have a fuel delivery issue as well as a drivetrain issue. The plugs and wires are all relatively new (about 1 year, 15K miles) and are OEM, not junk. I will try unplugging the AWD computer today to see if that makes a difference.

 

How long's it been since fuel filter replacement? I remember one time taking a trip in a friend's car and he filled up at some Joe's garage gas station out in the middle of nowhere. Not long afterwards it starting bucking and sputtering. We pulled over and looked everything over and then hit the road again. Everything was fine again intially, but then the same thing starting happening as we drove up the next hill. Classic fuel starvation symptoms so we removed the filter and blew on it and it was all clogged up. This black gook started running out of it too. We were pretty sure "Joe's garage" had been dumping used motor oil and god knows what else in his underground fuel tank and it ended up in my friend's gas tank. Anyway, could be that you got a load of bad gas and something similar happened. Just a thought, it's not always computer/sensor related.

PS>> Also look at the fuel pump. My old Scirocco fuel pump went up off and on for a while, causing behavior that mimicked a clogged fuel filter too (until it dies altogether).

 

Shaking at 60 sounds like its missing on a cyl or two. Low fuel pressure shoudn't cause a shake..You may have a bad coil affecting two cylinders at a time. But you need to get it to do it to troubleshoot. I hate guessing. Costly. Idleing high could be a vacuum leak. Give us more clue's


Dick