engine missing and long gear changes

[vsute3.8]

hi guys recently had a guy put a secondhand engine in my beloved vs series 111 s pack auto ute , hes now not answering his phone and im $1800 deep into this fix , problem is its missing under load when its hot, like cruising on the freeway and at the lights it shutters and almost stalls , ive had the injectors professionally cleaned and new spark plugs and few other things , after the injector clean and replacement it now bangs hard into gear and takes ages to change gears when driving . ive used random parts from my old engine like the TPS IAC and cleaned everything i can but nothing is helping , the long hard gear changing is a big worry , any ideas on how to fix either of these two problems ? thanks in advance

 

[Comcal76]

Check for fault codes, write down the codes you get then pull the 20A engine fuse in the engine bay for 5 minutes, this will clear the fault codes then restart the car and let it idle for a minute or two, now drive around the block then recheck codes.

https://forums.justcommodores.com.a...nd-comprehensive-dtc-error-codes-list.179140/

 

[Lex]

Missing under load sounds like leads.
Gear changes sounds like tps.
But as Comcal76 said, scan for codes first.

 

[vsute3.8]

gear box is fixed was the tps little black plastic thing fits on the acuaul throttle , but its still missing and almost stalling when it heats up , will scan for codes ,