Cyl 1 misfire/running rich

Hello All, Got a tough one for ya. Yes I've been searching for days so any insight would be very helpful.

Recently bought my son a 2000 taco with a 3rz.

She throws a p0301 code randomly and I can see cyl 1 misfire on my Alltel. I have documents showing on 2/8 that plugs, wires, and 1/3 coil was replaced. Also a fuel clean kit whatever that means.

The guy sold me the truck right after the stuff was done, he knew it was missing beforehand hence the mechanic docs. However it never threw a code until a couple days later (this, im sure is due to the brand new plugs but i'll get into this later). He is working with me on getting some money back so I really don't want to get into that conversation here. I'll also add the truck runs smooth when its not missing also during high rpms.

Now here is what I've done trying to track this down.

replaced the egc, its easy enough to replace. it had a little bit of water coming out of the firewall side larger vacuum hose. No change

Injectors, moved 1 to 2 and 2 to 1, cleaned, inspected and replaced o rings. (not the rubber insulators though. No change

Vacuum tubes, Silicone tubes all round.

Coils, swapped with no change

Plugs, Now here's where I'm Thinking its running rich and the cyl 1 misfire is actually a symptom and not the issue. truck ran fine with no cel after they replaced the plugs. thing is when I went to swap plugs around (NO CHANGE BTW) they were black and sooted....looked like they had been in there for years.

So, not sure what would make it run rich and really even IF it is. I nee to find where my altel will show me AFRs but even if I did im not sure what a good ratio would be. Also another thought is ....Would a valve check/adjustment be a good idea here?

Any thoughts on this would be greatly appreciated.

oh also it had a real dirty aftermarket filter I just cleaned.

 

oh forgot,

all cyl compression is right at 140

 

Yes a valve check/adjustment would be a good idea, especially if it hasn't been done. If out of spec, a proper adjustment can improve compression. What's the mileage? Compression looks decent though. Within range. You got the same code for Cyl 1 after swapping injectors around? I was going to suggest a possible bad injector. Now Idk.

 

179k milage.

yep same code after injector swap


gonna look into valve adjustment this weekend.

 

so I just pulled off the cover and tried to align for tdc and found this....

 

What would be the easiest way to fix the cam alignment?

 

Undo em and rotate it

 

All you need is a trusty Hanes manual and youtube

 

looking for a fsm atm....think I found one

 

I'm pretty sure this is what the issue it. surprised it runs!!

 

Good thing it’s only one notch off. Hopefully it didn’t cause any damage. It is an interference engine I believe

 

Check the rest of the timing. Down at the crankshaft pulley. If it’s good, be sure not to undo the chain from the timing gear on the driver side camshaft. Use zip ties to keep the chain on the teeth.

 

I'm thinking the driver side is off. what do you think?

 

yeah its looking like its the drivers side to me. think I can move it over a tooth without tearing apart the front end? not sure how to stop the tensioner from moving

 

I wouldn't jump into removing that and realigning the cam unless you can prove that it was removed previously.
Check your valve clearances first. Normal maintenance does not require removal of the cam, so it should never get misaligned like that.

 

yeah im pretty sure it's been messed with

 

Make sure to check the timing mark down at the crankshaft. Sheesh at this point I don’t know what to tell you. Whoever buggered with that was careless. If the timing marks on the chain are non existent there’s no way to know for sure they’re even on the right teeth.

 

Ok. Got all the marks lined up how they are supposed to. Pulled the timing gear off the intake cam and moved it over a tooth, then pulled the exhaust cam completely and aligned the dots on the gears. After torqueing down the exhaust cam I checked the intake cam bolts and they were like maybe 5 ft lbs! So I re torqued those as well.

Quickly checked shims and they are all off....so tomorrow I'm doing those lol

 

After thinking about it with the cam gears being off from one another and then the timing sprocket being off a tooth I think they sortof offset eachother a little and the ecu was just like whatever ill make it run lol

 

Figuring out what shim to put back in requires some math. Hope you’re ok with math