Glossary of Terms

backfire, popback - Fuel ignites in either the intake or the exhaust system

CKP - crankshaft position sensor

CMP - camshaft position sensor

cuts out, misses - a steady pulsation or the inability of the engine to maintain a consistent RPM

DLC - data link connector (previously called "engine [1][2]diagnostic connector")

detonation, spark knock - a mild to severe ping, especially under loaded engine conditions

ECT - engine coolant temperature sensor

EGR - exhaust gas recirculation valve and system

generator - previously called "alternator"

hard start - the engine takes longer than usual to start, even though it is able to crank normally.

hesitation, sag, stumble - There is a moment of lack of response when the throttle is opened. This can occur at all vehicle speeds. If it is severe enough, the engine may stall.

IAT - intake air temperature sensor

IAC - idle air control valve

lack of power, sluggish - the engine has less than expected power, with little or no increase in vehicle speed when the throttle is opened.

MAP - manifold absolute pressure sensor

MIL - malfunction indicator lamp

MTV - manifold tuning valve

MVLPS - manual valve lever position switch (previously called "park/neutral switch")

O2S - oxygen sensor - left oxygen sensor when there are two sensors)

O2SR - right oxygen sensor

PCM - powertrain control module

poor fuel economy - There is significantly less fuel mileage than other vehicles of the same design and configuration.

rough, unstable, or erratic idle stalling - The engine runs unevenly at idle and causes the engine to shake if it is severe enough. The engine idle RPM may vary (called "hunting"). This condition may cause stalling if it is severe enough.

start & stall - The engine starts but immediately dies.

surge - engine RPM fluctuation without corresponding change in throttle position sensor

TPS - throttle position sensor

VSS - vehicle speed sensor