lonewolfrx

So i swapped in an s5 motor into my s4 a while ago and just recently it started having that 3800 rpm hesitation. I cleaned and redid the grounds and im pretty sure my injectors were newish when i installed them. Any other ideas on why i would still have it?

RotaryEvolution

iTrader: (30)

add a ground wire off the brown/black wire to the pressure sensor and be sure you cleaned the ground ring terminal at the rear rotor housing under the UIM(this ring terminal is for the ECU/injector grounds).

if those aren't it then you may have low fuel pressure and or clogged fuel filter. double check the TPS, set the timing and replace your plugs/wires. general maintenance is important. lastly send the injectors off to be serviced again, not knowing if they are flowing properly will just keep you from adding it to your checklist.

lonewolfrx

i thought adding grounds to the pressure sensor was only for the 86 model? the plugs and wires are brand new. ill check the tps n timing when i see the car again. thanks

lonewolfrx

changed the tps. hesitation gone. thanks. now to fix the alignment and maybe drive it to las vegas to my new place.