The air and fuel mixture needs to be within the proper spec for the engine to run perfectly, and an EGR valve problem will cause this mixture to be off. #2. Reduced Fuel Economy. Reduced fuel efficiency is one of the common symptoms of a bad EGR valve. Carbon deposits can build up inside the valve and cause it to get stuck in the open position. It was not leaking at the gasket between the EGR valve and the engine. It was leaking from the middle of the EGR part itself, in the center rod part. The EGR valve does have another paper like gasket there but its an internal gasket in the middle of the EGR valve. Check the engine light. When the fuel to air ratio is high, you will have the check engine light coming on. The engine control module controls all the sensors, and if a sensor in your car misfunctions, it will light up the check engine light on your dashboard. 2. Fuel smell from exhaust. 1) Toyota 1MZ-FE Engine Oil Consumption Issues. Oil leaks can be a prevalent issue in many different makes and models. Unfortunately, one of the downfalls of the Toyota 1MZ-FE is that they are prone to oil leaks and engine sludge buildup. This can be a cause for concern as oil leaks can cause damage to an engine over time. If not the egr valve can cause stuff like that with no codes. Also the VGT can stick !Usually with a code thou. Try lubing the little lever on the turbo with some Penetrating oil see if that helps! Next time your by the shop have 68 stroke out the turbo to make sure its calibrated or holding it's calibration. Your EGR valve probably is opened by a vacuum. If the vacuum line between the intake manifold and the EGR valve were to be leaking, it would cause both the driveability problems and the P0401 code. First, inspect or replace that line. A vacuum leak could also affect the shift points on the transmission. The valve has a SEAL to keep High Pressure air from the Turbo from escaping. The air from the Turbo contains some oil (very normal). The SEAL goes bad and cannot be replaced. There are two weep holes on the EGR, one front and one back. The longer it goes the messier it will become. The oil needed for the 3.0 is critical since it should be under the right conditions. When you use the wrong oil, it will cause a congealing issue, which can block tiny oil parts in the engine. Also, when you take your car to the mechanics, double-check the oils they are using to avoid issues. Exhaust Gas Recirculation (EGR) Valve 3.How to fix an EGR cooler leak? Install a new clamp and lock it to tight at the leaking part. Choose the same size of butt joint band clamps as diameter of pipe. Fix the leak with an EGR coolant repair kit, it only takes a few hours to finish the job and you could find installation video on Youtube. Remove the EGR system. uBJh.

can a bad egr valve cause oil leak