Hi. I'm the owner of a 2008 Volvo S60, and I've been having a problem with my vehicle for exactly one month today that has bedeviled my mechanic of thirty years and even the specialists at my regional Volvo dealer. Hopefully, someone here at this forum has insight that might point us in the right direction.

Beginning on January 29, 2020, my 2008 Volvo S60 began to experience erratic fuel pressure problems. The car seemed to partly lose power, and the "Check Engine" light came on. Here's a timeline of events and a list of things my mechanic has already done, but did not solve the problem:

1/29/2020

1. First sign of trouble. “Check Engine” light came on for first time, and car seemed to be at only 80% of normal power and was oddly shaky when stopped at intersections.

2. Drove car into private repair shop.

2/11/2020

3. “Check Engine” light came on again. Car struggled to move (much more than on 1/29/2020).

4. Car unsafe to drive. Needed AAA tow into same private repair shop.

2/21/2020

5. NO CHECK ENGINE light, but car struggled again, similar to incident on 2/11/2020.

6. At one point, car shut down entirely…with all lights on dashboard display panel ON. Car would not start.

7. Restarted car after several minutes.

8. AAA tow to private repair shop again. Mechanic unable to find source of problem. Restarted car, and it drove normally while testing with mechanic.



NOTES:

· Problem tended to show up shortly or immediately after making a right turn after having driven on free way or up steep hill.

· Car “sputters” before failure.

My mechanic has already performed the following tasks, but these have not solved the problem:

1. Replaced fuel pump (brand new, certified Volvo fuel pump).

2. Replaced fuel filters.

3. Replaced fuel rail pressure sensor.

4. Replaced new air mass sensors.

5. Replaced #1 oxygen sensor.

6. Replaced all ignition coils and spark plugs.

One more theory that my mechanic offered, but has not yet explored, is that rodents might have chewed through some of the vehicle's internal electrical wiring or connections. This is a possibility: the mechanic found rodent waste in the engine block, and I do know that rodents are present in my neighborhood.

I am hoping that the experts and enthusiasts here can provide some insight that will be helpful. Thank you in advance.

 

what fault codes did the CEL indicate? Assume there were misfires or fuel trip codes - important to note if the misfires were random or always the same cylinders. Did they replace the fuel pump relay (not sure if your car also has an injector relay but the older models did and that was a potential no start)? Did they inspect the wiring harness/connectors going from the firewall to the coils for cracked connectors etc? Did they do a smoke test for possible torn vacuum lines/intake boots?

Yes, its quite possible rodents can damage wiring and the intermittant nature you've described suggests something electrical not mechanical. Fairly common issue here in New England (cold garage, warm engine...) I've found acorns in the most unusual places (like between the hood and its insulating blanket).