I am working on e38 ecu swapped gmt400 big block truck. I have a tune that is working, but has drive ability issues. So far, I been trying to continuously go over the engine it self trying to verify and weed out any mechanical issues but still seem to be somewhat stuck with following:
Surging cold start up idle
Hesitation on throttle when cold and when hot. Runs better when lightly warm
Highway driving specifically seem to be poor performance
On full or close to full throttle application, wide band reads output as lean initially and then ramps to commanded AFR.
Was looking for some ideas on what should I be looking in to or if something being missed that might be obvious just looking at the run screen shot.
I am almost thinking of getting a single plane efi style intake manifold and try with it instead.
Engine is 488ci, brodix oval port RR heads, cam is HR73353-114 233/233 @.050" .353"/.353" Lobe Lift .600"/.600" Valve Lift 114 LSA, shorty headers, 1000cc FIC injectors, stock 454 vortec intake manifold lightly ported, ported throttle body inlet with LS3 throttle body, ls1 coil packs, ls3 maf, stock cool air box, about 8.9:1 compression. Injectors are large for future expansion.
Edit: IS301-1000H fuel injector clinic