2015.5 V60 2.0T
#3 cylinder exhaust valve burnt. I Removed and replaced cylinder head, machine shop removed burnt valves and seals to spec by Volvo. After install and start up, everything worked perfect. After about 100 miles the car had a misfire on #2. Swapped #1 and #2 ignition coils. It ran fine for about 10 miles and now sluggish when accelerating. No check engine light. Smooth as butter at idle. New plugs, injectors, cleaned MAF, new air filter, new oil and filter, new and clean coolant, inter cooler hoses fine, any solutions to sluggish acceleration?

 

Any stored codes? it may take a few miles for a code to be generated but I'd start with checking for air leaks/torn vaccuum lines/torn or loose intake air tubes, loose connections etc - anything touched during the head r+r is in play. After that you will want to check compression, double check cam timing, fuel pressure to see if you can get any other clues. Did you determine the cause of the burnt valve? Any signs of consuming coolant suggesting a cracked head or head gasket leak?

 

I checked and cleaned all electrical connectors, vacuum lines, smoke tested, pressure tested, intercooler lines good with no tears or leaks. Pressure check cylinders and good at 190 psi. I finally got a code “P030200” #2 cylinder misfire detected, no check engine light at 25 mph, engine hesitating, I pushed through the surging and it smoothed out after I let up on the pedal a little. Got back on the gas pedal over 35 mph and worked perfectly. Im going to move #2 coil and plug to #1. I’ll post the findings.

coolant has stayed constant at max line and no color change. Oil is staying at full line, and not gaining any fluid. No milky fluid, just gold oil. No exhaust leaks or smell of fuel. No smoking gun on burnt valve.

 

I also forgot to mention that while the cylinder head was off, I replaced the piston heads. The oil consumption was too much. Volvo has a service bulitten for high oil consumption. And changed back to conventional oil rings and extra oil passages on the piston.

I finally figured out the issues. Since everything was new I did not double check the new parts being defective. The #2 spark plug was bad out of the box. I got a new one and worked great.