Power loss climbing hill, engine shuddering
 

Hello all... I'm new to the forum...

2006 S80 Turbo

When driving up hills, my 2006 Volvo S80 Turbo will sometimes begin shuddering and has a large power loss.

The check engine light does not come on most of the time this happens.

The engine has enough power to limp up the hill at 30mph - 50mph when this happens.

If i turn off the car and let it sit overnight, it usually starts back up with no problems.

Recently the car experienced the same problem, but with a flashing Check Engine Light. The power loss is much worse this time.

And now the problem has not fixed itself by waiting overnight.
I can start the car but it runs very rough, the CEL is still on (and sometimes flashing... sometimes constantly illuminated).

Has anyone else experienced this?
Does anyone here have suggestions for troubleshooting?

Thank you all in advance for any insight you may be able to offer.

Best wishes...

Not sure if this is a new car to you but what is the maintenance history or status of the vehicle fluids and filters?
Could be a bad coil, wire, or spark plug; fuel filter needs replacement, etc.; really, many, many things.
Which codes are thrown when hooked up to a scanner?

Typically "uphill-related" misfiring is caused by high tension ignition components being bad (which on this car is only the coil). The flashing engine light indicates a misfire currently happening, so it all fits. I can only guess that it didn't misfire enough to set the check engine light during some of those events. It looks like you can buy coil wires without the coil, aftermarket. Might fix it.

While the engine was missing and running rough, Advanced Auto hooked up an ODBII tester.

The check engine light was on, however the employee said there were no error codes being shown.

This car was bought new in my family.
All servicing was done on schedule.

Around 115,000 miles some of the valves burned up.
The mechanic at the Volvo dealership did the work and suggested the reason could be due to running 10% ethanol in the fuel.

Thank you for this suggestion! I will try it as the first attempt to solve the issue....

Replaced Ignition Coils & Spark Plugs
 

UPDATE:

A subsequent ODB2 test reported misfiring in cylinders 1 and 3.
The ODB2 software suggested replacing the ignition coils.

I replaced ignition coils on cylinders 1 and 3.
I replaced the spark plugs for all 5 cylinders.

Unfortunately, the problem of the engine "missing" and struggling to run persists....


On 9/21/2016 FireBirdParts suggested new coil wires may be the solution.
I did not replace the wires. That will be my next step.


If installing new coil wires does not solve the problem, does anyone here think the problem could be in the fuel injectors?


Thank you to anyone here who may have insight to share.