hello all, new here just got an 88 dl ea82 had blown head gasket and would barely run. I took it apart and checked everything, resealed it and got it running good. had check engine light on, codes 24,35,34 replaced purge cntl solenoid fixed the 35, found broken wire in harness for the code 24. Egr sol was not holding vac, replaced it with solenoid that held... still code 34? I pulled some diag trees from alldata and one of the first steps is to look for voltage at egr solenoid switching from 5v to 0v every 1.5 sec with green test connectors connected and key on. then if this does happen it goes straight to replace computer. and what do ya know that's what I get. Ive been working at shops for 20 years and whenever a diag tree leads to replace pcm in the first few lines it almost never fixes the prob. just thought id get some more ideas, never hurts. the clear codes green and clear connectors are under the hood. I may try to clear the codes then disconnect the battery tomorrow, just to make sure.

Open solenoid coil is a more common failure by far.

Might want to check that.