Engine - Momentary Hunting at Idle on Deceleration

84chevy08

Number: 83-T-83

Section: 6A (VI)

Date: April, 1984

Subject: IDLE SHAKE ON 3.8L (LC3) -
VIN CODE 9 ENGINES


Model and Year: 1982-83 MALIBU AND 1982-84
MONTE CARLO, EL CAMINO, IMPALA AND CAPRICE

TO: ALL CHEVROLET DEALERS


This cancels and supercedes Bulletin 83-T-83 dated September, 1983. This issue adds 1984 Impala and Caprice and clarifies by model and year, momentary hunting at idle and excessive idle shake.


MOMENTARY HUNTING AT IDLE (1982-83 MALIBU, 1982-84 MONTE CARLO AND EL CAMINO)

It is possible to encounter a momentary "hunting" at idle on deceleration brake stops. This condition can be minimized by setting the base idle (ISC retracted) to 500 RPM (released spec. was 475). Refer to 1983 Shop Manual, E2ME, Carb. 6C2-5, Idle Speed Adjustment, Items 9-11 for the procedure to make this adjustment.


EXCESSIVE IDLE SHAKE (ALL MODELS LISTED)

A harsh shake may occur at normal idle conditions, A/C on or off. This condition may be caused by grounded engine mounts which can be corrected by installing a shim, P/N 14082881, between the L.H. engine mount and the block and using three (3) longer bolts, P/N 435611. If the drive idle shake is improved, but not to an acceptable level, 6 mm of shims should also be installed between the R.H. mount and the block.