Lower Oil Pressure after doing Valve Cover Gasket

Hello,

So this weekend I changed the valve cover gaskets on my 95 4Runner because I was having an oil leak and the car was overheating so I got a new radiator as well. Before the job the car had no issues other than overheating because of a bad radiator. Now after putting it back together, at idle the car has the oil pressure gauge up to the first line and then once raising the rpms to around 2-3K RPM the oil pressure goes to the middle like normal and car runs fine. When going for a test drive around the parking lot the rpms dropped faster than usual when downshifting and if they dropped to <=1000 then it would shut off. I've checked all the vacuum lines and things that were taken off/apart and no luck. Are there any specific lines or assemblies to check for that could cause this problem?

Also quick PSA when turning the A/C on the rpms would bounce on idle between 1K and 1.5K give or take

Thanks in Advance for any advice or suggestions!

 

Your oil pressure sounds normal. At idle it will be low, at the first mark, and return to normal when you are driving. Mine does that too. Sorry cannot help you with the RPM issue.

 

Kind of sounds like my 2002. It would hunt for an idle with the AC on and I could make it go back to normal idle by turning off the AC or blipping the throttle.

For my car it wound up being the Throttle Body. Which when replaced, replaced the integrated TPS and the Pedal Position Sensor. The TPS was most suspect as I measured it and it was pretty far off at certain positions. However, the throttle body was massively gunked up and could have used a cleaning.

I would look at that area of the car. TPS/IAC/TB/MAF/TB and clean them up or replace. Search for vacuum leaks and cracked or petrified hoses.

 

Depending on the vehicle, idle hunting is often TPS, and idle air valve/stepper motor/whatever used to adjust idle. Did all the injectors get plugged in?

 

When the AC is on the idle is boosted to provide power for the engine to spin the ac compressor. That 1000 to 1500 RPM range is normal for the step up in engine speed and will cycle with the compressor so it is not hunting it is normal.

The 3VZ-E has a cold start actuator in the TB which has a wax actuated piston that is open when cold to elevate the idle speed to shorten warm up time. The AFM and the TB need to be well sealed with the air pipe/s that connect them together, properly seated and no age cracks in the pipes. The idle speed adjustment screw is located in the TB and faces the front of the engine. The o-ring seal on this screw is probably due for a replacement as they get hard and brittle with time. I put very small spring clips on all of the vacuum lines because these vacuum lines are old and with enough heat cycles they will eventually fail to seal well and all of these are a slip fit and rely on the hose to grip the steel tube or nipple they are pushed onto. Once they are disturbed with a valve cover job it's anyone's guess which one is not up to snuff.

As for the stalling out take a look at the throttle body and throttle plate and clean it with carb cleaner. If the engine is tired the valve cover breather pipe on the air intake pipe to the TB will be spewing a lot of oil residue and combustion blow by gasses straight into the intake which fouls the TB and the throttle plate with black carbon crap! There are three vacuum ports that adorn the top of the TB very near were the throttle plate sweeps past when it is almost closed. They may be fouled so pull the rubber lines and apply compressed air to the ports to make sure they are clear. One is to regulate the fuel pressure another for the EGR and the third for sucking vapors from the carbon trap on the fuel tank.

I hope the radiator solves the overheating. If it doesn't then the HG's maybe headed south and the #1 and #6 cylinders are the first ones to take a look at for super clean spark plugs. The coolant tends to steam clean the deposits from the electrodes on the spark plugs when the leak is bad enough and your losing coolant but its not external to the engine. But if the leak is slight you won't see steam in the exhaust either but the cooling system will be getting pressurized from the combustion getting into the cooling system. So feel the top hose after its warmed up and everything is at operating temperature. If it is really solid feeling then it might be a HG that is failing. You can try using a hydrocarbon sensing tester that analyses the coolant for combustion by products by changing color when they are present in the coolant.