Looking for an advice about the best course of action here.
I bought 2012 QX56 with 107k miles a month ago. Less than 500 miles later one morning a few seconds after pulling out of the parking spot it started shaking , "check engine soon" light came on as I drove through the parking lot. I read P0300 ("multiple misfires") with my OBD sensor. It could drive on a parking lot, but car was shaking (even in N and P) and there was certainly not enough power. I didn't take it on a road that day.
It sat for a few days. On a weekend I reset the error code, tried starting and stopping it a few times - and suddenly it was working fine again - idling quietly without any vibrations and with normal power. I drove it lightly for a week (another 50 miles) not trusting it to get on a highway. One day, just as I pulled out from a parking spot in the morning it started shuddering and shaking again and "check engine soon" came on. At this point it wouldn't rev up above 1.5k bouncing back.
I brought it to a Nissan dealer in my town. They read "codes for intake valve timing solenoids bank 1 and 2" and "using data monitor found readings are at 69 degrees and should only be at 0-5 degrees at idle". They suggested timing is off and quoted $1.8k to remove the timing cover to verify.
I towed the vehicle from Nissan dealer to Infiniti dealer where I knew the vehicle was serviced before. They diagnosed "DTC for P0011 P0021 INT/V BANK 1 and 2 as well as P0300" and "found high pressure fuel pump lift valve damage due to high pressure fuel pump not working properly". On the phone their technician explained what he visually saw after taking the HPFP out: HPFP lifter has a hole in it; lifter scored the walls of the timing chain cover where it floats; and HPFP cam lobe isn't egg-shaped anymore after lifter seizing and pushing on it.
Infiniti dealer wants $7k to replace HPFP, lifter, and cam - which would require taking the timing cover off.
I imagine it must be very similar to https://www.facebook.com/a1stratemobile ... 593704661/
where one of the mods of this forum commented about seeing multiple owners reporting similar problem.
My questions for the community are:
- should I pay Infiniti to do these repairs or is it widespread enough issue where Infiniti may admit it's a manufacturing defect?
- if I only replace the lifter and the pump (which will be much cheaper than $7k because timing cover doesn't need to come off) - how long should I expect the fix to last, assuming the cam's lobe and lifter's "pocket" in the timing chain cover are scored?
- with QX56, how different the pump and lifter replacement procedure is from what's described in howto-m56-q70-5-6-vk56vd-high-pressure- ... 25231.html
- anything else I should seriously consider replacing at this point, given potential secondary damage done by disintegrating lifter?