A buddy of mine had the same problem, so he added a second small turn signals(about 1,5" diameter) mounted just inside the wheel well on the bumper. The extra power it consumed returned the blinker flash to normal, and the 2nd blinker alerts drivers along side him.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed