I’m hoping some here can point in certain direction. At this point I’m pretty stumped. After replacing the head gasket on a 2013 Prius, just under 200k miles, I’m getting a hard misfire on cylinder 2. Below I will list out what has been done so far and any symptoms.
- Started with performing routine maintenance, car was running fine; replaced coil packs, spark plugs, water pump, EGR gaskets, sprayed intake cleaner into intake side of EGR pipe, and outer tie rod ends.
- Had an intermittent misfire, drove it around town and finally tripped a P0304 code
- Replaced cylinder 4 coil pack with one of the original coil packs and misfire went away
- Car was driven for about a day and had a hard misfire and P0304 code returned
- Inspected EGR system and found it dirty; Replaced EGR valve and Heat Exchanger, cleaned EGR pipe to Intake as well as intake in ultrasonic cleaner. All ports on intake are open and clean. Still had hard misfire
- Used Combustion Leak Detector and found Exhaust gases in coolant
- Replaced head gasket, as well as any other gasket touched in the process, verified timing when reassembling
- First start after head gasket replacement had misfire; using scan tool misfire monitor I could see it’s now misfiring on cylinder 2
- Verified all hoses and electrical connectors were properly connected
- Swapped Cylinder 2 and Cylinder 3 coil packs; misfire still on cylinder 2
- Swapped Cylinder 2 and Cylinder 3 spark plugs; misfire still on cylinder 2
- Swapped Cylinder 2 and Cylinder 1 injectors; misfire still on cylinder 2
At this point I’m lost on where to look next, if any of you have any ideas I would greatly appreciate any input
TLDR; Replaced head gasket, coil packs, spark plugs, water pump, EGR, cleaned intake and still getting misfire