Hi , Can anybody help please , Just recommisioning my 1991 gto ,Again 
, I have had the ecu rebuilt by the way doctor , again as that went faulty last year , But now when i drive the car ,And give it some welly the engine check light comes on , normal driving it’s okay, The ecu doctor sent me another ecu but it does the same ?? My cat over heat light has come on last year, so I linked the cables under the passenger seat , That made it go off ,but it has come back on again ?? Not sure if this is affecting the engine check light or making it come on ?? As usual any help would be really appreciated
Thanks Matt