Help please,


#1

car jumps from 2000rpms all the way down and goes back up all the time and bogs while it does it


#2

Could be a disconnected or leaking vacuum hose or a bad Idle Air Control (IAC) valve.


#3

Is the engine actually changing speed or is the tach showing a change and the engine not really changing?


#4

the engine is changing right along with the tach, my teacher asked me and all i could think of was a vacuum leak, so i just posted here


#5

Use your Haynes repair manual to find the idle air control valve (iac). Disconnect the electrical connector from the iac. If the idle stabilizes, you’ve found your culprit. Another possibility is the mass air flow sensor (MAF). Follow same procedure.