90 riviera code 42

so my 90 riniera will run fine for about seven miles and shoot me this code 42 and run really sluggish it has the 3.8 with a distributer less ignition

so my 90 riviera with the 3.8 will drive around for about 7 miles and the check engine lite comes on and shoots me a code 42 it starts to run really sluggish and if i reset the codes it will take another seven miles to come on

Code 42 = The Electronic Spark Timing (EST) signal did not change when the ECM applied bypass voltage to the ignition module. Check for faulty connections, or a faulty ignition control module (ICM).

Thats a timing related error usually. Sounds like the 3800s' favorite sensor to me. My money is on crank sensor / magnet. First thing I would do tho is remove the computer from under the coil packs. Clean off any corrosion etc and reassemble. Ive seen just that alone fix alot of weird ignition issues on 3800s. Check also the cable going under the coil packs to body. Should be passenger side, inside a small plastic box thats black on the fenderwall. Remove the nut and all teh cables. Make sure that stud isnt all rusted between the body and the stud itself. Remove it and clean it off , reassemble. Most times small ignition problems are nothing more then a bad ground. I start there first. If it continues after cleaning, and coil packs test good and such, my money be on that Crank sensor. I have seen it throw error 42 more then once...