i have no idea what type of motor that the troope even has but your exhuast manifold is gonna be under the hood and the very starting point of your exhaust(the part that touches the motor and gets real hot real quick)
My guess would be wheel balance.
16.0 staight for intake and exhaust valves
Where is the enginenumber located on a c190 isuzu engine
Lower the left,driver side exhaust pipe from the manifold, dont have to take all way out just undo three nuts from exhaust manifold, and three at rear of pipe, slide pipe to rear and possibly drob cross bracket below starter, I didn't have to but makes it easier, then just undo the two starter bolts and two wires from starter, and it will roll out between engine and frame.
find the marks on the pullys, they should line up with the 01234 marked on the faceplate of the timing belt cover, should show to be on 0 i beleive. use a timing gun
on the exhaust manifold.
The oxigen sensor can be found on the exhaust manifold or exhaust pipe
You have to remove the exhaust pipe from exhaust manifold on starter side. Now you have access. Get exhaust pipe to exhaust manifold gasket first, you will probably need to replace it after taking them apart.
exhaust gas
The EGR (Exhaust Gas Recirculation) valve on a 1985 Isuzu Trooper is typically located on the engine intake manifold, near the back of the engine. It connects to the exhaust manifold via a metal pipe. To access it, you may need to remove some components such as the air intake or other hoses for better visibility and reach. Always refer to a repair manual for specific details related to your vehicle's configuration.
remove intake manifold.
Under the water neck, where the upper radiator hose to connected to the intake manifold on top of the engine.
exaust gases
The first torque spec for Isuzu 2.6 exhaust manifold in 58 ft lb. It has a second torque spec which is 72 ft lb.
It is located on the flywheel.
On exhaust manifold.
The starter on a 94 Isuzu Trooper is located on the bottom, passenger side of the vehicle. It is found at the rear of the engine, at the flywheel.