2003 1.4 80 hp petrol engine in question. 150,000 km on the odometer. When starting cold, there is a tapping sound and the car jerks at low revs (1-2.5k). Tapping follows revs. Tapping and jerking disappears when the engine warms up. I don't know if the tapping and juddering are related.

 

No fault codes found.

 

Just changed:

Oil + filter.

 

Fuel filter.

 

Plugs, coil pack and leads.

 

Timing belt and water pump.

 

Serpentine belt.

 

Engine air filter.

 

MAP sensor.

 

Crankcase breather valve and its hose.

 

The motor mount is on the right side and the one next to the gearbox.

 

EVAP system load valve (was blocked. Evap system found to be working otherwise.)

 

Checked or cleaned:

 

Cleaned fuel injectors. Good spray pattern in all injectors.

 

Checked valve clearances. (0.20 intake and 0.30 exhaust) Replaced valve cover gasket.

 

Cleaned throttle body and inspected it's seal.

 

No oil or coolant leaks.

 

When the bonnet is open, a small hissing sound is heard from the front of the engine, from the right side, when standing in front of the car.

 

I don't know if the little hiss is normal. I tried to look for a vacuum leaks several times with carburetor cleaner, but i haven't found any leaks.

The brake booster seems to work normally.

 

My own quess is a vacuum leak. Gotta keep looking for it.

 

From what i have read these engines seems to be often tappy when cold. Im not sure if that's anything to worry about, but the juddering is just annoying.

 

 

Any helpful hints? 😊

I located the source of hissing and it seems to be coming from fuel pressure regulator. Hissing sound changes when i move the fuel line that attached to the regulator.

Could the regulator be partially clogged?