Engine low power runs rough

Car suddenly started to run rough under load. In neutral engine runs fine. No check engine light.

Year, make, model, mileage…?? Have you tried changing the fuel filter?

VW Passat 1999, 60k mi’s. Not sure if it has a fuel filter.
Looking for possibilities before I take it in to repair shop.

Is it a 4 cylinder turbo?
Is it a 6 cylinder?
Is it a diesel engine?
www.autozone.com shows an external fuel filter for the 4 cylinder engine.
It shows an external fuel filter/water separator for the 6 cylinder engine.
The fuel filter/water separator has a water drain valve that needs to be drained, from time to time.

1.8t 4 cyl gas engine. Owners mamual says there is no fuel filter. Only Diesel has a fuel filter

www.autozone.com says that the fuel filter, for the gasoline 4 cylinder is located in the engine compartment.
The car is at the mileage that a dirty fuel filter can cause performance problems. A good mechanic would change the fuel filter and check fuel pressure, at 2000rpm, in DRIVE.

Thx, I checked Auto Zone & they list the filter, relay & Pump.
I’ll look for the filter and determine if I can chg’g it myself, IF I can find it.
The Auto Zone picture may help locate it.

It could also be a bad coil or other ignition component.

I’ll know soon. I did get it to the repair shop. hopefully it’ll be rady later today.
Thx for all the input, it gave me options and cost estimates. I figure reapir is cheaper than replacing it with another used car.