Codes 27?, 36, 42... ARGHH!!

[stepho]

Hey guys I have a problem with my 93 z28. Oh my way to work it started acting weird. It revs up but it doesn't want to go faster than 35mph, and it jerks. Its a manual transmission and everything there feels solid... soo its got to be engine related.

I pulled the codes and got 13, 16, 27, 36, and 42.

13 is the oxygen sensor no biggie there right?
16 is the charging system, ok needs fixed but still not my current problem..
27 says this "2nd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 2nd or 4th gear switch was open when engine was first started." umm... ok maybe I am stupid but since its a manual it doesn't have gear switches right?

both 36 and 42 have something to do with EST or electronic spark timing... which I am guess is my problem

[Morley]

Your EST module is part of your memcal/calpack, the piece in the ECM that also has the PROM chip on it.
Before replacing that, check your knock sensor.