I just finished my 5vzfe swap and it starts up great, idles, comes up to temp, and drives really well. but as soon as i press the throttle all the way down; it stumbles and quickly dies. Them starts back up no problem.
I've tested and cleaned the MAF sensor, tested the TPS, new O2 sensor.

So i don't know what else to check at this point.

 

Check restriction on air intake....like dirty filter or perhaps varmints building nests in the air box infeed ducting.

Buckaroo

 

pretty sure thats not it, i forgot to mention it only happens under load; in neutral it seems to have no problem with WOT.

 

Did you hook up your obd2 port yet? check for codes, history codes. Then watch the live data, whats the ECT at? tps %?

 

I don't have an obd2 reader, but it is hooked up.
I don't know the exact ECT but it seems to read correctly on the cluster, the problem appears to happen the same if it's in open or closed loop.

 

I mean really your doing a swap and you don`t have a code reader at least!!

I think most of us have some sort of scanner to read real time data !!!~

As there are always going to be bugs to work out.

 

yeah well the budget dictates, and i can manually test components.
I really do need to get one though, clearly.
I'm having a hard time finding anyone with a similar problem. I hope it isn't the ECU...
I'm gonna change the fuel filter and that doesn't help i'm just going to have to save up for a reader

 

so i'm on my way to buy a new filter, i manage to get it to the gas station and fill it up.

The problem is gone

no hesitation or stumbling; i figure there was water or something in the tank.
I bought some gas treatment additive and i'll have to just keep and eye on it.

Now all that's wrong is a high idle because the EVAP equipment isn't completed.