Inconsistent RPM Rate After Gear Shift

[tfranks140]

I have an 04 Grand Prix gt and this problem has gone on for awhile now. I've taken it to two mechanics, the first one saying I simply needed a transmission fluid replacement and the other saying he couldn't figure it out. To explain the problem further, this usually only happens from 3rd gear to 4th, or from 4th down to 3rd, but once the shift is made the RPMs will surge up and down and will continue to do so until I let off the gas a bit or push harder on the gas. The second mechanic replaced the mass air flow sensor and MAP sensor in an unrelated issue, but told me about the p1811 code being thrown, and I'm guessing that had something to do with my problem. Just looking for advice on what could possibly be wrong and what to do about it.

[Turbocharged400sbc]

AFL valve oscillation due to wear of the valve body bores over time

it will continue to happen until the trans is rebuilt and the valvebody is machined for the Sonnax repair sleeves/valves.

learn to drive it so that you are the one stopping the occilation, then get back into the throttle, enjoy pissing people off from driving like a little old lady.

you could just get a Tripple edge performance reman VB and install it to fix that issue but then again the trans is probably close to needing a full overhaul too....why pay all that labor to have to redo it all when the trans clutches are gone.

save for a trans, change driving habits to limp along