My normally reliable '96 did something the other evening that I didn't like. I was on my way home after work, on the freeway, when there was a very brief deceleration
like hitting a gust of wind. I eased over to the right lane just in case, then it began to definitely surge. I gritted my teeth because the freeway is being widened and there are no emergency lanes for miles, but eventually I came to an off-ramp, and it ran just fine on the side street. I had my tablet and VAG-COM, but found no engine or trans codes. So after driving around awhile and finding nothing wrong, I tried the freeway again, as there is no other way to my house. Sure enough, just as I got to freeway speed and entered the lane, the thing started bucking again. Now I had gone past the last off-ramp for perhaps five miles, with hardly any safe places to stop ahead. As I came up on the following on-ramp, I pulled over onto the triangle of concrete between the freeway and on-ramp, with cars going by on each side at 60 mph. With the engine idling nicely, I considered what to do, then began to back down that on-ramp with the emergency blinkers on. Every time a bunch of accelerating cars came towards me from behind, I pulled over as far as I could and hoped nobody was looking at their phone. I finally made it back to the street, and once again could not get the engine to surge. I ended up driving back to work, and borrowed the ugly company Dodge cargo van.

Right now I have no clue what made it do that, but I had just filled the tank a few miles before. The surging was so brief that I'm not sure the engine was doing it, or the trans was. Next week I'm taking a different, safer freeway to test it, with a friend following me.

 

It started acting up right after filling the tank is a good clue. First thought is it could be bad fuel. Either it has water in it or is old and stale, or.................At least once a month I get a car with driveability problems with no obvious cause and it turns out to be bad gas .Not to scare you but I've seen an awful lot of fuel pumps fail soon after the tank has been filled also. Although, they usually just outright quit working, sometimes before the car leaves the station. Never have been able to come up with a reason why (I'm an auto tech, btw). Whether it's putting cold fuel into a tank with a hot pump (like when the tank is run fairly low) or what.
Best bet is, monitor the fuel pressure while driving and see what it does. If it's OK, I'd go back to a bad batch of fuel possibly.

 

chicken

 

nah...jk put some high quality fuel in it like 93+

 

Problem resolved: it was the fuel pump circuit, specifically a broken wire in the fuel tank. The car quit totally on Saturday, which in a way always makes the troubleshooting easier. After pulling the pump last night, it was obvious that one wire had a break, and in fact with a tug it came apart. Some terminal soldering and I'm back on the road!

 

A final update: after fixing the broken wire, that problem was gone, but now the car took as much as five or six seconds of cranking to start after not being driven for a while. Using VAG-COM to run the pump for that time instead made the engine start right up, so I suspected a leaking fuel hose in the tank. Tightening the hose clamps did nothing, so the other night I pulled the pump again and replaced the 20 year-old plastic hose with a foot of Gates submersible fuel line, which is about $30/foot at NAPA. This completely solved the long cranking issue, and I think the old plastic was just too hard to seal after being pulled off of the pump a couple of times.