Tundra 2008 Strange Misfire after Valve Cover Gasket Change

Hello everyone,
This is my first post here, I really need your help to figure out what happened to my monster
I have 2008 Tundra 5.7 V8 with 186,000 Miles. 1 Month ago I had misfire which was coming only during the morning with the check engine light blinking and when i switch off the car and turned on again it runs perfectly. So i decided to dig deep with the misfire and open 1 spark plug and found it soaked with oil, I visually inspected the valve covers and found both are leaking. so i decided to send the car to one garage (I'm located in Dubai so we are using the term garage ). The garage had the car for 1 day to do the valve cover gaskets, Spark Plugs seals and also replace the serpentine belt tensioner and idler pully. and they call me to come and take the car. And at this moment the sad story started. I took the car with test drive and it was running very smooth then suddenly it was hesitating and jerking. and Check engine Came and was blinking, we scanned the codes and we got a misfire in Cylinders 1,3,5,7 and Cam Sensors fault (I Can't recall the codes). Then the garage told me that replace the spark plugs and it will go fine and the old spark plugs are soaked with oil. So we ordered 8 new OEM spark Plugs and replaced them. We started the car. again misfiring but this time cylinder 6. we swapped the ignition coil but the same still misfire cylinder 6. but this is not the end. now the car is misfiring cylinder 1,2,3,4,5,6,7. and give Cam sensors fault + Crank Sensor + Oil Control Valve. Now the guys in this garage wants me to replace all the sensors but I'm not trusting them. and I don't want to though money by purchasing unnecessary parts. I called one friend for another opinion he is telling me that maybe i need to clean the injectors but he is more thinking that the car has timing issues and maybe the timing chain has jumped 1 teeth due to a bad tensioner.
What do you think ?

 

I would first have the truck towed to anywhere else, the people working on it are obviously clueless.

It sounds like there is a simple issue somewhere like a ground or plug that didn't get hooked up after the work was done. None of those codes seem related, which is why there is probably a single fault somewhere with the wiring that is tripping everything up. Replacing random sensors when those didn't have issue when you dropped the truck off is stupid like you said, and the tensioner you had replaced for the serpentine just controls the belt on the front of the vehicle, so there is no reason the timing chain should've been touched or should have any issues.

I can't really give any help, except I would check the wiring connections very closely especially around the back of the engine where it's hard to see and a connection could've been missed.

 

Thank snivilous for your answer. Regarding the timing issue, i think my friend meant to say that maybe the chain jumped one tooth due to a bad tensioner. I will have my car inspected in another workshop to check if I have timing issues.

 

Check to ensure they plugged in the oil control valve wire harnesses after reinstalling the valve covers.

 

So I have conducted a compression Test the values are:
Cyl1 : 175 psi
Cyl2 : 170 psi
Cyl3 : 140 psi
Cyl4 : 175 psi
Cyl5 : 146 psi
Cyl6 : 150 psi
Cyl7 : 160 psi
Cyl8 : 160 psi
Are those values normal, giving that the max difference is 35 psi. Do I have a jumped teeth or damaged my engine ?

 

I have checked, its properly plugged

 

Update:
Now 1 week and no one is able to diagnose what is wrong with the car, looks like I’m not dealing with professional people, we actually inspecting all the sensors and connections all looks and tests good. Also they were suspecting the VVT i failure due to oil collages as i have some sludge in the oil. So they are opining the valve covers to inspect. I’m not sure its a VVT i failure due to oil collages. Yes the car has oil sludge but this seams very old to develop a misfire in one day after a valve cover job. My final though is a bent or broken valve spring in bank 1. As the misfire is in bank 1 now. So my question is . If i have failed spring, i will still get compression higher than 140 psi in those cylinders. Please help me its 1 week now and I’m feeling that i cant find a professional that can fix my car in Dubai

 

Update:
Here is the summary of the problem and what have been done and checked so far:
1- This march my issue with misfire's started. I have misfire during morning, Car is shaking and when switching off and on the car run fine for 1 week then again misfire when i park the car.
2- I had a leaky valve cover gaskets and Spark Plugs leak.
3- Since i thought that doing the valve cover job with new spark plugs will solve the problem. unfortunately the problem got worse.
4- After the Valve Cover Job, I got misfire in whole bank 1 cylinders (1,3,5,7) With codes related to Cam Shaft, OCV and Crank shaft sensors + Also Random Misfire
5- Sometimes the misfire is recorded at 2,4,6 cylinders.
6- During the past two weeks, We re-open both valve covers, and timing Cover. Checked the valve train for any possible mechanical failure at valve springs, Lifter or Rocker all looks good. We checked the timing all marks are in position. during this process we replaced one chain tensioner in the driver side for the main chain. We also replaced some gaskets for the vvti.
7- After assembling everything now the car has a misfire only in cylinder 6.
8- Swapped the coil, spark plug, and injector and checked for any possible vacuum leak. still no hope and the misfire is still in cylinder 6.
9- My compression test for the cylinder 6 is 110 psi dry and 150 psi wet.
10- The car is damaging all the spark plug in cylinder 6 after 20 miles driving. so we put new spark plug in which we are testing before inserting it in cylinder and spark very well with clean blue spark. After replacing the spark plug the car run very smooth and then again back to misfire and we test the spark plug to find the spark is yellow and msifre.
11- Now We are checking all the wires and ECU.
12- Other possibility that I will check after making sure that the ECU and Wires are not the problem is checking the head gasket. as i'm suspecting that i have a coolant leak ( No overheating happened before)