1994 Toyota Camry Engine shudders on take off up hill in lo

Engine Performance problem
1994 Toyota Camry 4 cyl Two Wheel Drive Manual

The engine has plenty of power and idles well, never stalls. I just put in new spark plugs, but it still shudders when the engine is cold, in first gear, especially when going up hill. It accelerates smoothly under the same conditions after the engine warms up. I thought it was a clutch problem at first but the higher gears run smoothly and the transmission doesnt slip. The car has 293000 miles. The plugs were loose and the extensions were schorched. It had bosch plugs. I put in pk2 Denso plugs. The car has more power now. I dont know when the car was last tuned up but it has been a long time if ever. Four Cylinders.
Thank you for your attention.
Ross