I finally bought my 2nd dream car, the engine only had 40,000 miles on it.
Im not a mechanic but after the first mechanic misdiagnosed an issue
I suggested. (A failing clutch)
The mechanic assured me it was my timing chain was off.... on a 40,000 miles engine, keeping in mind its been garage every winter since 05 and driven by an older lady.
Assuming the mechanic who builds cars for a living and his $30,000 computer is right I let him do the work. He replaced the water pump as well and new gaskets, but left the old sprockets under the VTC cover on due to there being 0 wear and tear on the sprockets
and put in a new chain and gears. $1,400
Turns out, it was the the clutch.
So i asked another mechanic to put in the clutch. $1,400
i asked for exedy and when i showed up i saw i different part on the counter. but im told i now have and exedy stage 2 clutch.

issue fixed.... for about 20,000 miles.... then i have a misfire, but there is not really serious other issues and i was able to drive for thousands of miles fine.

but when i hit around 80,000 miles i get a misfire again and my car starts to bog down at idle and stall when the clutch was engaged. the check engine soon light starts flashing
trying to avoid mechanics, I replaced everything i possibly could, self teaching how to be a mechanic.
all NEW spark plugs, all NEW ignition coil overs, all NEW 02 sensors. new intake boot (hole in the old one), NEW air filter
NEW fuel pump. semi new battery, NEW PCV valve, NEW Hitachi Solenoid actuators.

Didnt fix the issue, starting to sweat a bit, i start up the G35 drive it down the road.
after a week diagnosis, im told Nissan/infinti made a part specifically for the G35/350z where you cant replace the outside solenoid you have to replace the inside where the retarder is.
VTC Cover assembly kit ($2600)
im told he cant find the parts but if i could buy them he would install them. Im told 100% if the timing chain has been done the only other issue it could be is the VTC cover assembly kit.

i say "your 100% sure"
"YUP" he says
turns out those parts have 0 ETA and would be coming form japan.... but no clue when...
i managed to get my hands on the very last VTC covers in the USA took over 1 whole month to get them------------, so if you need 04-06 G35/350z VTC cover and assembly im selling them for $2400 OBO

By this time my car has been in the shop for over 2 months, and I've lost my job, my lease is also up in 1 month, still no working car.

so i get my car towed to another mechanic. Im told its the exhaust valve is most likely stuck open that's why its dying at a idle and still runs while engaged..
quoted $1400, after this I'm not really sure where to turn, I've spent the entire amount I've spent on the car itself trying to keep it alive and it only has 80,000 miles on it.... is it just my luck or WTF is going on with this G35 rev addition

misdiagnosis--$1400 (3 weeks)
clutch------------$1400 (3 weeks)
trying to fix it---$700 (3 days)
misdiagnosis---$2600 (2 months)
exhaust valve--$1400 (2 weeks)
------------nearly 1/4 of a year in a shop--------------------$7000 being repairs-----on a 05 with 80k miles?-------I've seen cars that are totaled and revived for less--- what is going on?
ANY INFO IS GREATLY APPRECIATED

 

Lesson learned, don't just throw a bunch of parts at a car hoping something will fix the issue.

EXACTLY what code was it throwing, if the CEL is on that's the ECM telling you almost exactly what the problem is.

By throwing a bunch of other parts at the car you are potentially introducing OTHER PROBLEMS, just because a part is "new" doesn't mean it's going to function properly, sometimes you get bad parts.

Step 1 of shade tree mechanic, LEARN TO DIAGNOSE THE PROBLEM.

 

so when they diagnose that its the vtc cover itself was the issue; because the replaced solenoid actuators worked fine when they tested it.
and im told by the current mechanic that the previous mechanic had the right idea... but it was $2600 mistake

so if 2 mechanics agree that those parts needed to be replaced to fix the issue, you recommend just... not misdiagnosing?

 

Ok so there's actually 4 different individually replaceable components, the two intake cam actuators, and the two exhaust cam magnet retarders.

The intake cam actuators are just a solenoid that operates on a duty cycle, it's not uncommon for them to get crudded up after 100k+ miles and need to be replaced, quick easy and cheap.

The exhaust cam magnet retarders are not something that commonly fails, and I've never even heard of both failing at the same time, ever. You can test the actuator with a multimeter and compare the two sides to see if there's a problem. The part is also insanely expensive for the rev-up so you usually just get a set of used ones if there is an issue.

But none of these things will cause a misfire or affect idle rpm. You could literally unplug all of them and the engine will run fine (with a CEL), it will just be very gutless since you're essentially cutting 50hp off of the motor.

However, if the engine was throwing code P0075 or P0081 then something broke in the intake solenoids and that would be a proper diagnosis, P0078 or P0084 for the exhaust magnet retarder. Each of those codes corresponds to ONE PIECE OF EQUIPMENT that would need to be replaced, typically you don't replace these things in pairs.

However if you were throwing codes P0011 or P0021 for the intake side, or P0014, P0024 for the exhaust side then that's usually the corresponding cam sensor failing, sometimes a crank sensor failing. Those items WILL affect idle, also cause a misfire, and are prone to failure anyways if you have 100k miles on the car. If you have one cam sensor fail it's not a bad practice to just replace all of them with new Hitachi or OEM Genuine Nissan. It's normally the plastic housing becoming brittle, micro cracks, and contaminating the winding with engine oil that kills your cam sensor, crank sensors just get a lot of abuse due to their location on the bottom of the engine.

P0011 and P0021 can also be caused by low oil pressure (since those solenoids are using oil pressure to actuate the cams), oil pressure should definitely be checked if you're getting BOTH codes.

It's also possible to break the adjustable cam sprocket internally, this is harder to diagnose, normally if you have gone through the normal troubleshooting procedure, replaced the solenoid, the sensor, and are still getting the P0011 OR P0021, not both, then it's time to pull the timing chain and disassemble the sprocket to look for a fractured section on the inside.

Exactly which code/s are you throwing?

 

I believe it was P0024 and P0021 I deleted the pictures, its been in the shop for 3 months now. Currently getting removed from the vehicle to diagnosis if its the Exhaust valve.
still barley 80,000 miles.
VVT solenoids were replaced new Hitachi

 

im told if i put my story about my G35 on reddit itd be an anomaly

I was told to spend $2600 on new VTC covers which i did. My original VTC covers had 0 issues.
As it turns out my timing chain snapped on which the mechanics who installed the VTC covers and said its 1 of 2 issues the chain or the VTC covers...…. (the mechanic didn't even check the chain)
which caused the piston to possibly kiss the valves which means the engine needs a whole rebuild.
But when i was told to buy the VTC covers it was because Nissan makes the actuator on the inside of the cover and you cant just replace the solenoids on the outside of the VTC cover you also have to replace the cover itself.
Which now im finding out if your replacing the VTC cover; you should be removing the old sprockets and chain off with it. So you'd need $2600 for a VTC cover and $1400 for a chain replacement all because the service engine soon light came on.
which is practically the cost of the engine. But now its going through full rebuild.....
is it just my luck that out of 2 years of researching indestructible cars finding a bullet proof engine that I just happen to buy the 1 G35 where its chain snaps and it takes a bullet?

 

Yeah I've never even heard of the chain snapping, that's REALLY weird.