Alright guys I have an issue I can’t seem to figure out and hopefully I can get some good advice. This is for my j35 2003 CLS6. I get this hesitation when driven cold. I also get a random hesitation from 1st-2nd(only at WOT) and sometimes when I park the car for 5-15 minutes when I 1st drive it it hesitates and sputters for 30 seconds then drives fine.
Things I changed. Rebuilt J35a3, new clutch & flywheel, recently rebuilt transmission, rebuilt & ported heads, rebuilt injectors, new oem coilpacks & sparkplugs, new walbro fuel pump, runners, manifold & throttle freshly ported & polished, new map, throttle position, intake air, coolant temperature, crank position sensors, used low mile fuel pressure regulator, new fuel return line hose, added a ground wire
This happened with my j32 engine as well

 

Is your TPS calibrated correctly and did you use aftermarket MAP or TPS? Check your timing and lastly, check for exhaust obstructions like a clogged cat.

 

tps is oem and calibrated to 9.4. Timing was checked and I have a test pipe

 

Sounds like you need to run some diagnosis on your spark, air and fuel to make sure that you're getting the correct and expected values according to OEM specs. You've got a lot of aftermarket parts going on, my suspicion is that something isn't reporting correctly or that you have a faulting part. It's going to take a some instrument diagnosing to determine. A PicoScope is probably your best bet to find out.

 

Problem fixed. The engine ground wire wasn’t in the right place

 

where is that ground wire located I need to check mine because my 01 cl is doing the same this it hesitates to accelerate here and there and it happened when I changed my valve covers and what not happened a day after so not sure if I touched something no misfire codes no cel no vsa nothing no lights on and iacv throttle body was changed along with fuel pump and main fuel relay that’s located under the dash and that still didn’t fix my problem when I drive the car to a store leave it off and 15 minutes later I come back and the car turns off then dies I have to keep my foot on the gas to keep it alive then it doesn’t die someone recommended I change the 3 sensors one behind the intake plenum the fan switch and coolant sensor in order to get rid of that I also used sea foam to clean the fuel injectors and nothing