3.4 dies @ Idle & Driving (Help)

Aloha Gang, I have a 03 3.4 with a black top trd supercharger & 7th injector kit . had the kit and rebuilt the charger about a year ago and has been running fine till the last few weeks .
i also deleted the dual cats around that time due to it being restricted .

so the issue im having is that the truck dies after idling in park for 10-15 minutes. when restarting the truck i need to let it sit for about 5 then try to crank it again. most times it fires back up but sometimes it starts the dies out again. the other day i was driving down a hill and then it died out again but in drive . lost my breaks and powersteering but luckly was able to pull into a shopping center without hitting anybody . towed it home and was told it was possibly a MAF sesnor so i picked one up . the original one was a denso MAF that i also replaced about a year and a half ago . keep in mind that there is no codes that come up or check engine lights when this happens.

i replaced the mass airflow today and it seems to be running better , i also did a smoke test for vacuum leaks and cleaned the electronic throttle body . im just worried to drive down a steep hill and dying out again.

i logged all the readings via scan gauge tool .

Original MAF readings -
@idle in park (will die out within 10/15 mins)
185 eng temp
RPM- 690-700
MAF G/S @ 4.12
throttle position @ 13.7%
SHORT FUEL TRIM @ 20.53
LONG FUEL TRIM @ -7.8

@idle in drive
rpm -600
mAF G/S - 3.6
Throttle position @ 13.3
Short fuel trim @ 3.91 to 4.25 (fluctuates)
Long fuel trim @19.53


-----------------------------------
replaced the mass airflow sensor with a autozone "NEW"
I know its not OEM but nobody has one on hand in hawaii


( new MAF sensor )
@ idle in park
rpm @700 average
maf g/s: 4.8 to 5 at 700rpm
short fuel trim @ 3.91 to 1.8
Long fuel trim @ -7.8

idle in drive
Rpm- 598-600
maf g/s: 4.3
Short fuel trim @4.69 to 3.12
Long Fuel trim @ -7.8




after logging my readings i noted that with the original MAF my short and Long fuel trims seemed off ?
when replacing the MAF they seemed better .
could it be just a failing MAF sensor that is throwing the fueling off causing it to die out possibly flooding the cylinders with fuel or starving it ?
any imput or suggestions would greatly help .

 

Start off with an OEM sensor from the dealership because of all the fake ones in fake denso boxes.
Then recheck the fuel trims,
The engine cutting out like that typically is a vacuum leak

 

non of the dealerships in my area have instock thats why i ended up picking up the "aftermarket " one
im gonna order a oem but for the mean time like i noted i couldnt find any vaccum leaks and after changing the maf with the new one the fuel trims looked better based off my understanding of fuel trims

 

UPDATE- after changing the MAF it runs longer but still dies out . just did another check for vaccum leaks but did not find anything

 

When was your fuel filter last changed?

That will not trip any codes.

 

@Bivouac year ago -

so when i bought the truck it had issues -so far a year ago i had changed
timing belt & water pump
fuel filter , installed the urd 7th injector and fuel pump
maF, ended up being a restricted cat (cut out and straight piped )
both upstream and downstream 02 sensors
cam sensor and crank sensor while doing timing


you think i could be dropping fuel pressure ? i know was thinking it has to be with airflow or fuel related . but idk im not a mechanic lol but after changing those parts about a year ago i havent adjusted anything or added anything else it just randomly happened

 

It can not hurt to check with a gauge.

From your description it sure sounds that way.

You did use denso fuel Pump??.

When you check for codes if your losing your ecm ground it might be long enough to clear any codes..

that would also shut your engine off.

charging system working correct ?? Voltage drops to low the ECM Shuts down

EFI and Circuit Open relays coils getting hot and shutting down to things cool off.

A few out of the box ideas.

Best of luck.

 

@Bivouac i havent checked with a gauge
the urd kit comes with the upgraded fuel pump . charging system works good based of what i had seen . hooked my multimeter up and solid 13.9 vdc at both alt and bat. i cant find the open circuit relay based off of my year i looked under the dash for hours and could not find it . i read in a few forums that it sits under the relay box but still couldnt find it