2000 Isuzu Rodeo LS ~ check engine & reduced power lights

If you did actually need a throttle body you could
get it for less than $800 new or get a used one &
install yourself in about an hour.

Only got 4 small bolts holding it on.

The only reason for a throttle body is if it is
drive by wire & you need a tacm motor on it
& that motor is not avail separately

Do some internet research on that issues

I would be looking at fuel pressure at the motor,
fuel trim on a road test, oxygen sensors, ignition
issues long before I got stumped & ended up at the
throttle body

If it is has a motor turn on the key & have someone
slowly push the gas pedel

If the throttle plate opens & then snaps closed,not
the problem

Also consider a gas filter that has been never changed in
10 years or a blocked exhaust converter or exhaust leaks
before the converter effecting fuel adjustment

Need to know in detail what was tested & how by that shop

Here is the definition of the code.

Possible causes - Faulty Throttle Actuator Control (TAC) module
- Throttle Actuator Control (TAC) module harness is open or shorted
- Throttle Actuator Control (TAC) module circuit poor electrical connection (loose or broken wires)

P1516 CHEVROLET Description The Throttle Actuator Control (TAC) module contains data which is essential for proper TAC operation. The TAC module continuously test the integrity of this data. When the TAC module is unable to write or read data to and from Random Access Memory (RAM), or the TAC module is unable to correctly read data from the flash memory or and internal TAC module processor fault is detected and the Detected Trouble Code (DTC) is set.
Read more: http://engine-codes.com/p1516_chevrolet.html#ixzz286Gl3cSo

what code is coming up on the check engine light?

Engine may be idling to high. Check for vacuum leak.

Have the ABS pump ECM checked (it is separate from the main ECM), try to catch it early. I bought a transmission last year. This is typical 98-02 Rodeo behavior.

Check the fuel pressure it could be the fuel pump or pressure regulator.

it's the EGR valve and can be fixed by anyone. It involves disconnecting the battery, remove electrical connection, and removing 2 screws and cleaning the surface area well and replacing it as well as the gasket. A new EGR valve runs around $120 and trust me you can fix this and save hundreds!

reduced power usally points toward a gas pedal to throttle correlation meaning the drive by wire system is where the problem is

all electrical power must come from an alternator an a good batterie to store it please ck your alternator or have it ck by an parts store clerk if the altrenator is bad (must develop 13 0r 14.5 volts output. anyting above that ,the alt is bad!) change it then ck your batterie an batterie connections terminals and all the 80 amp fuses on the fuses box nicolas

I just went through this with my 2001 rodeo and the dealer needed to replace several parts over several weeks because they could not get the problem to go away.

-APP/throttle pos. sensor needs calibration/replacement
-air idle control needs replacing
-throttle body needs replacement
After months of going back and forth to the deal with the same problem, the throttle body was replaced last week and the problem has dissapeared....for now...