90 Jetta, power loss when warm

I didn't notice this because my drive to work is only
about 12 minutes. After about 20 minutes or so on the
highway, it bucks or just looses power. So I was shifting
back and forth between 4th and 5th, which would refresh
the car and it would run fine for a minute or two.
Then I discovered I could leave it in 5th and just periodically
let off on the gas for a second (fully)and then hit the gas
again. It was a bit strange speeding up and then slowing
down constantly. Bad for gas milage I'm sure.

So I figure it's electrical, something is telling it to go lean,
maybie the O2 sensor or wiring. Not sure why this doesn't happen
in the first 15 minutes. Hoping for advice before playing with
the O2 sensor.

Thanks again.
Les

B Briggs wrote:
> Hi Les,
>
> My Golf of the same vintage was losing power at high revs and some new
> plugs solved the problem.
>
> I'm not saying that's your problem but it's always a good idea to
> check the basics first, if you haven't already. How's the fuel
> filter? How about Vacuum leaks? The cap and rotor? Sometimes one
> problem can lead to another.
>
> Best of luck.

Thanks, that looks like a train of thought I can jump aboard.
I'll take my time since the problem doesn't occur on my
normal commute.

Hi Les,

My Golf of the same vintage was losing power at high revs and some new
plugs solved the problem.

I'm not saying that's your problem but it's always a good idea to
check the basics first, if you haven't already. How's the fuel
filter? How about Vacuum leaks? The cap and rotor? Sometimes one
problem can lead to another.

Best of luck.

Does this problem appear when temperatures are near or below freezing,
and when the humidity is high?

There have been similar reports of these symptoms in A2s over the
years, and speculation that they are due to ice blocking the air
cleaner element. Ice crystals can form in the air intake even when
the ambient temperature is above freezing, due to the pressure drop in
the intake. Just a thought...

On Oct 27, 5:56*am, IRv > wrote:
> I didn't notice this because my drive to work is only
> about 12 minutes. *After about 20 minutes or so on the
> highway, it bucks or just looses power...