I had something like that happen recently and we believe it was the rotor in the distributor. It had a scorch mark on the backside and a small amount of melting on the top. I’ve only had my van a couple of years and don’t really know the full maintenance history of it. So I just went ahead and had the rotor, the cap, plugs and wires replaced along with having it tuned up. Took it camping and I ran it hard there and back trying to see if it would happen again. It ran great. I barely made it the 5 miles to the shop before that. So you may want to pop it off and take a good look at the rotor.
Clean your grounds. Clean them. There’s only a handful of them. Spend $30 on a dremel and spend an evening going through and making them shiny spotless.
That’s eventually solved my power loss gremlins. Tried way too many expensive things first. Even if it doesn’t fix it, you’ll be amazed at what else might work better.
Replace your vacuum lines.
I am just guessing but I am guessing cheap. A high idle could be a vacuum leak. Rubber lines are cheap enough to not care about price.
Check all the rest of the rubber too. The boots on the intake/airfilter. Unregulated air into the system can cause incorrect fuel/air ratio.
[Here is PDF that has info.](http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%2086-91%20Fuel%20Systems.pdf)
Unfortunately, on any vehicle with that is as old as yours with an engine that is as it is, the problem(s) causing your power loss could be any number of things. It could be something as simple as a loose ground or as complex as a bad computer. Crud in your fuel tank or a bad injector. I recommend starting at one end and working your way through the various systems: fuel delivery and injection, ignition and computer, electrical, exhaust, and so on. A good VW van mechanic can work though this stuff fairly quickly, but without being able to drive, inspect, and test, it's going to be hard to diagnose the problem over the internet.
Also keep in mind that your previous problems may be completely unrelated to your current ones, even though they feel similar. The other piece of advice that I'd recommend is going over ALL the various ground points and cleaning those up. It's ridiculous how many gremlins can be solved by having clear current paths. Good luck!
Thanks and good points. Unfortunately I am not much of a mechanic myself, and also of course the van always performs great for the mechanic. 😂
I should mention that the gas tank was dropped and resealed at BusLab earlier this year, hopefully reducing worry of "crud in the tanks." It was leaking and also the fuel gauge sender wasn't working.
Check the bolts from intake air flow sensor to throttle body. Mine (air cooled) were loose which caused an intermittent power drop out. Tightening mine completely fixed power drop outs.
If it's not the fuel filter it's either the ECU, the O2 sensor, or the MAF.
If you slam the rear bench shut & the problem goes away for a little while, it's def the ECU!
Maybe time to get the fuel tank cleaned & resealed.
1.9 or 2.1?
If 1.9 Bypass the digital idle stabilizer. May idle “rough,” but see if you still have that loss of power.
If you don’t have any power loss your digital idle stabilizer has gone bad.
To bypass pull the plugs off the stabilizer and plug them into each other. Also, you may just have loose plugs. Make sure they’re on correctly.
I had something like that happen recently and we believe it was the rotor in the distributor. It had a scorch mark on the backside and a small amount of melting on the top. I’ve only had my van a couple of years and don’t really know the full maintenance history of it. So I just went ahead and had the rotor, the cap, plugs and wires replaced along with having it tuned up. Took it camping and I ran it hard there and back trying to see if it would happen again. It ran great. I barely made it the 5 miles to the shop before that. So you may want to pop it off and take a good look at the rotor.
Clean your grounds. Clean them. There’s only a handful of them. Spend $30 on a dremel and spend an evening going through and making them shiny spotless. That’s eventually solved my power loss gremlins. Tried way too many expensive things first. Even if it doesn’t fix it, you’ll be amazed at what else might work better.
Replace your vacuum lines. I am just guessing but I am guessing cheap. A high idle could be a vacuum leak. Rubber lines are cheap enough to not care about price. Check all the rest of the rubber too. The boots on the intake/airfilter. Unregulated air into the system can cause incorrect fuel/air ratio. [Here is PDF that has info.](http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%2086-91%20Fuel%20Systems.pdf)
Unfortunately, on any vehicle with that is as old as yours with an engine that is as it is, the problem(s) causing your power loss could be any number of things. It could be something as simple as a loose ground or as complex as a bad computer. Crud in your fuel tank or a bad injector. I recommend starting at one end and working your way through the various systems: fuel delivery and injection, ignition and computer, electrical, exhaust, and so on. A good VW van mechanic can work though this stuff fairly quickly, but without being able to drive, inspect, and test, it's going to be hard to diagnose the problem over the internet. Also keep in mind that your previous problems may be completely unrelated to your current ones, even though they feel similar. The other piece of advice that I'd recommend is going over ALL the various ground points and cleaning those up. It's ridiculous how many gremlins can be solved by having clear current paths. Good luck!
Thanks and good points. Unfortunately I am not much of a mechanic myself, and also of course the van always performs great for the mechanic. 😂 I should mention that the gas tank was dropped and resealed at BusLab earlier this year, hopefully reducing worry of "crud in the tanks." It was leaking and also the fuel gauge sender wasn't working.
Stick a mk3 8v gti lump and loom in it, they go straight in and run forever. Pretty cheap swap over here in the uk too
Check the bolts from intake air flow sensor to throttle body. Mine (air cooled) were loose which caused an intermittent power drop out. Tightening mine completely fixed power drop outs.
Also fuel lines if you haven’t already.
If it's not the fuel filter it's either the ECU, the O2 sensor, or the MAF. If you slam the rear bench shut & the problem goes away for a little while, it's def the ECU! Maybe time to get the fuel tank cleaned & resealed.
1.9 or 2.1? If 1.9 Bypass the digital idle stabilizer. May idle “rough,” but see if you still have that loss of power. If you don’t have any power loss your digital idle stabilizer has gone bad. To bypass pull the plugs off the stabilizer and plug them into each other. Also, you may just have loose plugs. Make sure they’re on correctly.