Engine: B5204: Volvo V70 engine issue

[MantasR]

Volvo V70 engine issue

Hello. So I have 1999 Volvo V70 with 2.0 petrol turbo engine. It has some kind of engine issue, that my local mechanics can't solve. Once you turn the engine on, leave it on idle, everything seems fine, it runs smoothly, no issues. But after 5-10 minutes rpms drops to the point that engine runs kinda unwillingly. If I press the accelerator and keep rpms above 2000, everything's fine. Anything below that, and the engine is "choking and stuttering" and eventually stalls. Parts that has been changed: VVT and VVT solenoid, fuel pump and filters, throttle valve, ignition coils, sparkplugs. But the issue still persists. If anyone has any advice, i would appreciate that. Thanks in advance.

[850T5orP80T5]

I had a 10 year nightmare with a very similar issue. Main dealer had my V70 mk1 for 2 weeks and £900 later still an issue.

Another garage changed the throttle body but still the same, air ducts were changed.

In the end i bought a new mass air flow sensor and finally solved the issue.

[Luxobarge]

Is the engine management light on?

Are there any ECU fault codes?

Failing that, it could be a vacuum leak, well worth thoroughly checking all the vacuum lines.

[MantasR]

There's no engine management light on on the dashboard. Only fault code that I had was VVT related. And it was gone one VVT has been replaced. I'll try to check all the vacuum lines, again.

[SteveSarre]

Hi MantasR

Do you have a code reader that you can use to monitor live data?

Do the cheap OBD2 dongles and the Torque app work on your car?

If you can, I suggest monitoring various important live data readings eg Mass air flow, throttle valve position, manifold pressure, various temperature sensors, O2 sensors etc, and see if one or more of those values changes unexpectedly when the engine start running badly.

Some values should also change smoothly when throttle pedal position, or RPM change smoothly. If the values jump, then that might point to a fault.

Hope that helps,
Steve