Here is the " basic check " with a scanner (it should pass this test) ;Do the following " live data" test with engine hot (normal operating temperature , Closed loop).


1-Fuel Trim (Short TermFuel Trim –STFT & Long Term Fuel Trim –LTFT )

Should be between +10% and - 10%
If so, your engine is OK . Otherwise ( if it is +/- 20 % or so , check injectors ,fuel pump etc. )

(PS. When engine is cold , not all sensors are working ).

2-RPM
Idle RPM 650-800 .

3-Spark Advance (Ignition Timing )
15-25 degree at idle
About 45 degrees at high idle

4- O2 Sensors
B1(bank one-cylinder #1 side )
S1(sensor –before catalytic converter( CC) – upstream of CC )
S2( sensor after catalytic converter(CC) – downstream of CC )

One monitors the engine the other monitors the catalytic converter .
Voltage should be between 0.1 -0.9 Volt ( 0.450 V most efficient )

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Also ,check if there is any "pending code" and "emission test readiness" lights ( green, yellow , red ) , all of these will give you some clues about the puzzle you are dealing with .

Again this is a very basic test . You may need to search for other live data values for further diagnostic work . You-Tube could be a good source .

Good luck,

<o</o