I own a 1989 5.7 iroc. 50 k original miles and I am original owner. Throwing a code 51. suggestions? Thank you

 

The memcal usually isn’t the problem. You should try ecm replacement first.

 

where is ECM located and how hard to remove? THX again

 

It’s located under the dash on a bracket on the passengers side.
there are two 7mm screws I think that hold the bracket to the dash frame.

 

thank you. Thinking about using Module Experts for repair. Any idea if they are a good one? Thank again!

 

I have never heard of them. You can get a reman ecm at RockAuto.com
the service is a 1227165.
https://www.rockauto.com/en/catalog/...computer),2896
if you find your car has a Hypertech memcal or a piggyback chip adapter I would think those could cause the code.

 

car is still factory - I have never made any changes to it. Like to get a better chip and more performance.

While I am an old jet fighter mechanic, USAF - I am for sure not versed well enough in cars to mess with things too much. Thx again.

 

Does the car run ok, or did it start having issues?
Every vehicle I worked on that threw a 51 was running like crap and needed an ECM.

 

what is weird, is it is very intermittent. When cold out, 40's here in South Carolina, runs great. Sporadic check engine, like it loses a cylinder, but keeps running. When hot out, more often and stays on. But will still run. always start as well. Thx for helping me.