tiger38117

Trying to sort out a problem on my new-to-me ‘82. I have owned/sorted out CFI and TPI vettes before but this issue is new to me.

When driving under normal city traffic throttle (i.e. pretty light), there is a pause/surge before it shifts from 2 to 3. When it reaches about 3k RPM where the shift would normally be occur, it will hang there for a couple seconds, then “surge” or “buck” lightly 2 or 3 times, then it shifts. The 1-2 and 3-4 shifts are fine. Heavier throttle/harder acceleration and the shift is normal. Seems to be worse when AC is on.

I have also been chasing the normal CFI inconsistent idle problems, but as of last night I think I have that sorted out. The shifting issue remains, though.

Ideas?

Thanks

Buccaneer

What was your idle issue fix and at MPH is this occurring approx?

tiger38117

Vacuum leaks, replaced EGR, replaced CTS, reset base timing.

I have been paying more attention to tach than speedo when it happens but I would say 25-30 mph. Where you would get a 2-3 shift in normal city driving like pulling away from a stop light.

Buccaneer

It almost sounds like a converter issue (lockup), but the speed is a tad early. Usually around 40-45mph for lockup. Does it do it also under WOT? If so, something is going on your your trans, but I am not a tranny expert. You may want to find a good qualified transmission guy that knows about a 700R4.

L-46man

So a little 'chuggle-bump' right at 35 is 'normal' as it makes up it's mind to LOCK or Not.. Also depends on throttle position and engine vacuum.

Unkahal

capnron3

funny u say just purchased an 82 this past year and just noticed a pause/or stumble with AC running on slow accelerations and back roads find on fast accelerations, so I now leave it in third on back roads with top speeds of 50mph . the tranny was rebuilt last sept and the rear also with 3,70 gears nice response overall othe then that rides find with sidemounted headers and sidepipes removed airpump and its never had the O2 sensor on and itg idles find with AC on or off lots of power wish I could find ID number on block to see if its the original well good with your hope this info mite help

Gunfighter13

Hypertech ThermoMaster Power Chips will fix the early converter lockup. The chips will not let the lockup engage until 45 mph. You have to run a cooler T-Stat and good fuel.