85 300D 179000

Generally the cruise works pretty well. Lately I've experienced an issue early into my commute drive where I hit cruise and the car keeps accelerating. Doesn't matter if I lock the speed but moving the lever up or down. Manual disengage works correctly. Resume will have it start to accelerate, I hesitate to say "uncontrolled acceleration". After a while, says 10 more mins of driving all is fine and CC works fully correctly. One other thing observed is that while cruising along on cruise, once in a while it cuts out, only for a split second and then it cuts back in. This doesn't happen a lot, maybe twice over 100 miles. I remember doing some CC work on my earlier owned 83's but my understanding of this is the 84/85 have a lot of different ways to control cruise, the tach, the EGR etc. Crappy switch or amp or pickup?
Thanks for any info

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.