Tip and stumble at at stop and go. Red lights , Stop sign. Normal driving.

[Tim Cucci]

Very slight stumble when leaving a dead stop during normal driving. Other than that the car idles, responds, hauls a$$, smokes the tires. I have not checked the sparkplugs yet? The car has cut out and popped at WOT like it ovverreved and didn’t shift out of 2nd quick enough? Slight Stumble is at take off only.
TPS .46 to 4.59
MAF Trans and 3.5 sensor
No EGR
Good Vacuum and 42 lb idle and 60 WOT FP. 17/18 boost
AFR 14/7 at idle. 10.5 at WOT
Idle 750/800
TT 5.7
50 lb. MSD
TA49
Stretch IC
Alky

 

[salvageV6]

Leave the scanmaster on O2 setting (default when turned on) and look for low or high numbers when the stumble occurs should be easy to do off a stop.
Could be lean or rich numbers showing for a couple of seconds while it stumbles.
TPS at .46 at idle is off needs to be below .44 volts when running, engine off when setting usually .42 works well.

 

[Tim Cucci]

I’ll check O2 tomorrow and reset TPS .

 

[TurboTGuy]

I'm having the same issue, stumble on tip in.

TPS readings are good. Put in new plugs, no change.

I have TA street aluminum heads, NGK 9 plugs gapped at a tight .22

Not sure what's going on.

 

[TTA308]

I’ll check O2 tomorrow and reset TPS .

What is the IAC at warm idle? Either way it will change when you adjust the TPS.

 

[TTA308]

Forgot to add I set mine at operating temp between 10-15, check what yours is at before you adjust TPS, ( so you know which way it moved )then check after TPS adj.

 

[TurboBob]

some things I have seen cause tip-in stumble:
bad TPS : a slight dead spot on the TPS can cause this, the idle and WOT readings will be fine, hard to diagnose. swapping it out is a decent test
mismatched chip and injectors: we used to see this with the lucas injectors, when using a chip set up for bosch/rochesters.
cam sensor 180 out: it happens...

other things, plugs, wires, ignition, injectors, MAF, tune out of whack.....

Bob

 

[TurboWh1]

Been there..... Check all vacuum hoses, etc. Sounds like a vacuum leak. I found mine with a smoke machine. Throttle blade shafts seals and vacuum block were leaking. You can buy a cheap smoke machine on Amazon if you dare to shop there

 

[Tim Cucci]

I think I got it! Ouch! I’ve done cam sensors many times! Some how, some way, the cam sensor was 180 out! Dot on gear and green dot were pointing at driver side instead of passenger side at 25* past TDC. I pulled it out and reinstalled it correctly and the car runs GREAT! No more stumble! Oh I did put in some new spark plugs too. Although the car fired right up something was tapping loud and settled down, not sure what that was?? Oil pump or cam sensor maybe from turning shaft to line up with the sensor??