I've been chasing an idle problem on my '94 E320 wagon also, except my problem is that the idle is too low, and then erratic - hunting and surging from 400 to 900 RPM and frequently stalling. The car runs perfectly fine otherwise, pulling like a freight train at full throttle and holding a nice steady speed with the Tempomat engaged. I most recently replaced the ETA with a remanufactured unit from BBA, and while it's better, with much more responsive throttle coming off idle and fewer stalling episodes, it's still hunting and surging.

The folks at BBA have issued an RMA for me to return the unit under warranty, but I'm beginning to suspect the T/LLR unit. Both upper and lower engine wiring harnesses have already been replaced, along with the OVP relay and a slew of other parts. There are no significant vacuum leaks and I'm not getting any codes on the DM or pins 8 or 14.

Can anyone tell me what the T/LLR unit does and how it generally acts when it goes bad? Thanks in advance.

Best REgards,
Rob

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Robert Fini

'12 ML350 BlueTec, 111k
'06 E320CDI (x2)
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 72k
'97 C36AMG, 325k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)