1992 240 Engine Pulsing

1992 Volvo 240 GL

check engine light came one read back codes:
121
232

replaced the original Bosch MAF with a new one from Volvo

now the engine is pulsing when idle

able to keep it running and drive with foot on throttle while idle.

any additional concerns I should troubleshoot?

Check for vacuumleaks and make sure the throttle and it’s idle screw is corectly aligned.

vocajun said:

1992 Volvo 240 GL...

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Disconnect IAC's plug, and start engine

Ok with highway type driving?

Check for a torn intake duct. They rub on the strut tower commonly when installed incorrectly.

Spray around with brake cleaner and listen for a change in idle= airleak.


The 1992 LH2.4 system will compensate for small airleaks, but if there is a big enough hole somewhere, the engine will idle poorly.