Sudden spike in fuel consumption.

I posted a problem about my '92 Grand Prix LE (v6 3.1L) a few weeks ago in here. Changing the Ignition Module seems to have taken care of the stalling problem. However, since that problem surfaced, my car has
been running horribly.
It never was great on gas but when i first bought the car 4 yrs ago, i did on average 425 km (264 miles) on a 60L (15.85 gal) tank. However, ever since my stalling problem, i only do 280 km (174 miles).
Ever since i got the ignition module fixed (using my old coils), the car hesitates whenever i give it gas from a standstill position (or even a slow roll). The car is very sluggish... sometimes it feels like I'm pulling a trailer with a heavy load. My mechanic cleaned the idling sensor and checked the EGR valve but he can't seem to see what is the cause.
I'm starting to suspect a transmission problem. Any ideas what could be the problem here as this came about so sudden.
TIA
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Try manually shifting the transmission down then up. Does that improve the acceleration?
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I had coil packs changed on my Lumina (3.1 engine) and was told the control module and coils should be changed together. The car may need to have the onboard computer reset. Roy
wrote:

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ROY BRAGG wrote:

How does one reset the onboard computer... i know on the '92 Grand Prix, the computer isn't that soffisticated.
As far as the exhaust goes, it seems like before.. not noticeable changes but i fear it may not pass the emission test due this February since it's running so rich now.
Curious as to what would cause it to hesitate.
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