looks like a new ecm for the 90

check engine lite came on and a code 42 was set which is for the electronic spark timing. was told before changing ecm to try installing a new ignition module as that maybe the culprit and it's a lot cheaper.

well i did that today and reset computer and fired her up. lite didn't come on and thought i had fixed it. WRONG. took it out to go to a cruise show and about halfway there light came on and car sputtered a bit. straightenned out a bit and got to show. it was running a tad rough but i figured it needed a good run. when i got there ran the codes and now came up with a code32 which is the egr system.

i guess i will be looking at a new ecm for it as originally suspected.

The EGR system will cause the car to sputter, and run a bit rough. You may need to do the diagnostics on that before condemning the ECM, even tho the ECM may be bad. If you have the service manual, just follow the tree for 32, and see if it winds up as a simple vacuum problem, or something similar. If you do not have the manual, P/M me, and I'll send you the info.

got the manual and i appreciate the help. from what i saw around it appears that if the ecm wasn't replaced it was unusual. i figured ecm as it has changed numbers completely and car was running with out that code showing up before i did the module. the only other thing that shows up is after the ecm codes are displayed (which is number 4) it shows a number 7 and then displays err where the code is shown. can't find anywhere what that 7 unit covers. 

I show code 4 as Outside Air Temp Sensor Circuit, and code 7 as Solar(Sun Load) Sensor Open.
If your car has the electronic A/C, these codes would pertain to that.

joel on my 90 i have electronic climate control and any codes are thru that for heat and a/c.  the engine codes are read on speedometer. where the average gas mileage is shows what section of computer it is checking. #1 is the ccm and #4 is the ecm. the trouble codes are displayed where the numbers for the mph is read.  after it checked the ecm (4) and showed the trouble code 32 it displayed a #7 as the section of computer it was checking and where the trouble codes are shown it had err. got a new ecm and wasn't too bad on price. $144.00 and that was thru a chevy dealer. the only thing that i will have to see if there is an updated prom for it which will be another $100.00  and if not i could use the old one. will have to get it in  maybe tonight.