Question for someone out there who has access to a Volvo Service Manual for the non turbo twin cam version for 1990. LH 2.4.

Friend of mine check engine light came on. Using the wrong info in a Chilton manual, plugged the test probe into socket 6 then tested for stored codes.

Got a 2-3-4 when plugged into socket six. Cannot find a definition.

When I checked using socket 2, got a 1-1-3 code. This is after six days on a NEW O2 sensor. Cleaned and checked wiring and all seems OK. Will know in AM if code cleared after driving.

Milage went from 7 to 14 after replacement of temp sensor for ECU, O2 sensor, and fuel pressure regulator by a shop prior to this problem. I replaced the broken fuel return line which raised the mpg to 20. Was getting 26 prior to 7 mpg drop.

Engine does not idle without pedal assistance until at full engine temp, yet still may die.

AMM disconnected or connected does not seem to affect engine running.

Vacuum hoses have been removed, checked and replaced.

Any ideas in addition to the code definition?

Any body have a known good spare 016 AMM that can be had for an economical price just in case current is bad.

Thanks,

Duane

Duane, I'd been having similar troubles to what you've been describing lately, and after a number of mis-steps (including a new O2 sensor), the solution was a new throttle Position Sensor switch.

The new switch helped somewhat at first, and then I PROPERLY adjusted the switch using the feeler guage method as described in the 700 FAQs.

Also, big hose that leads to the throttle body had a small tear in it, one that was no visible from above. I only noticed the tear after removing the hose to more easily adjust the TPS. I've patch it temporarily, until I can get a replacement.

My idle no longer hunts and rolls. No more two-footed driving.

Good luck.

1-1-3: mixture too lean or rich

2-3-4: Throttle position switch signal missing at idle