I am in the process of replacing the pod-type air filter, that has been on my V6 since I bought it, with a cyclonic action filter housing from a 60 series Land Cruiser. I had to take off the black plastic duct running from the throttle body to the air filter to modify it, and to get that out I had to take off the balance pipe that connects the fronts of the plenum chambers for each bank of cylinders.

When I took the balance pipe off I noticed that the inside of the intake was covered in oil and gritty black carbon deposits 

The oil is no concern as it comes from the crankcase breather which is plumbed into the intake. But the black crap has me worried. From what I can figure it is probably getting in from the exhaust through the EGR valve. I hate think what effect it is having on the valves seating properly and what wear it is causing to my lovely smooth cylinder walls

Here is a photo looking into one of the plenum chambers with the balance pipe off.



Has anyone seen this on their GV or any other EGR equipped vehicle?

Please discuss.

Thats carbon man. Get a bottle of intake cleaner and a rag made of actual MATERIAL and spray the rag and put it in the intake and put a screw driver in the center of it and rub the walls.

Then after spray the sides just a bit and put it back together.

Now this is a 2.5?? If so start the truck up with the black in take tube off and rev the motor to 1500 rpm and spray the throtle body but go past the Mas Air and do this for a few seconds and let truck idle do again a few times and this will clean the intake and valves out.

Make sure u do a oil change after u do this.

So nice to see this subject come up on my 58th birthday.

My 2001 2.5 GV had a check engine light a while back that I fooled the trucklet into dis-illuminating the dash idiot light.  When I checekd for codes, it was a bad EGR.  Weather was somewhat cold.  Others have mentioned a similar EGR code when temps are low.

Found new (used, less than 20k miles) EGR valve at Hawk in Merlin, Oregon (30 miles North of me).  HAve not installd yet.  No further problem with codes or service engine light.  Seems to run pretty good for a 145k miles used up vehicle.

It does start pretty badly sometimes, tho, esp when cold or damp weather.

Bottom line, I am wondering if this carbon deposit problem could be some of the cause of my concern.  145k miles is a lot.  ALso seems to be low powered (torque) when early in day.  OTOH, when well warmed up, runs like a top. esp on freeways and up good long hills with OD off.

Glad the trans makes up for some of the underpower.

ANy comments that might help?  Should I pull the balance tube and look?

We are stock but for K&N air filter and BFG AT KO's (29 inch).  Is our daily driver.

Thanks, Pat

Comon problem in cold climates.

My EGR is doing the same thing now on my GV its sizeing closed I could careless but possible cleaning it could help they carbon up most egrs dont work tell mid rpms.

My CEL comes on every few times now due to the EGR valve.

Try cleaning it.