[xmw]

hello i recently bought a 2004 vw Passat gls 4motion with a 1.8t and five speed manual the car is having misfire problems
i have replaced coils and plugs with nkg plugs and coils
i have checked pcv system and maf has been replaced
its giving me all the misfire codes and two codes for the bank one o2 sensor
code p1103 heating bank 1 performance to low and code p0139 bank one sensor 2 response is two slow no signal no communication
car has 154000k miles and timing was done at 80k miles
lmk if u have any other questions i really need help getting to the bottom of this issue
thx

 

[AndreasPassat]

Your timing belt is due for a change. Change interval is 75k miles.
While doing a timing belt service, you'll need to replace all of the other components that make contact with the timing belt.
Water pump, idler bearing, tensioner.
Complete kits are sold like these https://www.ecstuning.com/Volkswagen-Passat_B5-FWD-1.8T/Engine/Timing/Timing_Belt_Kit/

You'll want to pop off the valve cover too.
Inspect the plastic guide shoes on the CCT (cam chain tensioner). They are known to disintegrate over time especially if conventional oil was used for any length time during the life of the engine.

If you're indeed getting all of the misfire codes P0300, P0301, P0302, P0303 and P0304 I would suspect the plastic guide shoes on the CCT right away.

As for those o2 sensor codes, might want to pull those out and inspect the condition of them. They should have a very light greyish color to them. If they're all caked up with oil they are probably junk.
Not 100% sure but I think the change interval for o2 sensors is 100k miles.

With this amount of miles, you're at the point in time where general maintenance is going to be a necessity.

All of the other 1.8 aficionados can chime in about oil sludge and turbo issues. I'm a V6 guy.

Oh, I do know that the oil dipstick and crankcase breather are also prone to dry rot and decay causing vacuum leaks.

 

[xmw]

Update timing belt was done at 143000 and car is getting way to much fuel plugs r coated and oil was contaminated what could cause this

 

[xmw]

I took off the throttle body and found a good amount of fuel in the intake. it's noticeably wet and brand new spark plugs Have a lot of carbon buildup. I'm gonna test fuel pressure and replace spark plugs I think the fuel pressure regulator may have a tear allowing fuel to go back into the intake and causing the hard start and over fueling

 

[xmw]

Update fuel pressure regulator was definitely bad it was letting alot of fuel into the intake and it was mostly Ending up in cylinder number 4 causing the main misfire code but some fuel was also going to the other cylinders causing the other codes it also could have caused the o2 sensor to fail and I'm sure the rings and the oil r contaminated with fuel as well
Anyway tomorrow I find out exactly how it's running

 

[PZ]

I would check compression on all cylinders as excess fuel can lead to ring wear on the cylinder walls.