Removing the shut off plunger is a good start, but the problem could be a bad connection somewhere or a chaffed wire shorting. Being intermittent makes it difficult to track. Also try disconnecting the CPS, when it is causing the problem, it could be failing.
Grant H.
1995 6.5 turbo GMC K2500 extra cab 4x4 pickup, PMD under bumper, mechanical wastegate, 228,000 miles, rebuilt engine, 4.10 diff, 16 mpg
1994 6.5 turbo GMC K2500 4x4 suburban #9 resistor, PMD in the bumper, mechanical waste gate, 226,000 miles, new engine, 0 miles. 3.73 diff, 16 mpg
1982 4x4 shortbed 6.2 Chev 260,000 miles untouched motor 17 MPG 4.27 diff. Best thing I ever owned, since 1992.