1981 Oldsmobile Cutlass Engine backfires coming off idle

GSSNIPE

MEMBER
1981 OLDSMOBILE CUTLASS
V8
2WD
AUTOMATIC
60,000 MILES

We have a new rebuilt 307 bored.40 over, 6 to 1 rockers, msd igniton and new distributor, edlebrock 600 cfm carb and edlebrock performer intake. New Transmission with BM shift and 2000 stall torque converter. We took the car had the timing of the distrbutor and cam checked and adjusted all of the rolling rockers. The engine starts and idles perfect but if as you drive if you come off idle (start driving from stopped position) it will hesitate, then backfire, then run beautiful. If you are driving along and punch it, it runs perfect.

Saturday, October 4th, 2008 AT 2:11 PM

1 Reply

MERLIN2021

MECHANIC
17,250 POSTS

Can be timing too advanced, vacuum leak, or carb need mixture adjustment. With the work done here, the factory timing spec may not work. Put someone in the car foot on brake and in drive, adjust timming while gas is given and advance until you hear it ping, then back of just a bit, road test, use a tachometer and adjust mixture to obtain highest idle. Last use a can of spray gumout, spray vac lines and manifold area, when the idle changes, you have found a leak.

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Saturday, October 4th, 2008 AT 2:24 PM