1996 5vz-fe Slight hesitation at WOT

On my 96 3.4L I just got all my clutch parts replaced (and my worn out rear main seal) and it feels really good over all, but now that I can actually get on the gas and open up the throttle without slipping, I noticed that there is a very slight hesitation at WOT and in the upper RPM range. mainly I notice it in 2nd gear, WOT around 4,000 RPMs. Stock engine, not built-up, cancelled EGR.


My initial guess is that the A/F ratio is getting whacked out at the higher RPM, And maybe my injectors need to be serviced?

What do you think my first Avenue of attack should be in figuring out why this is happening?

My fuel pump is fairly new, within the last 60,000.

Again, it’s a very slight hesitation, it’s barely noticeable, I only noticed it when I was trying to send it as fast as she can go off the line onto the highway. Didn’t notice it in 1st gear, noticed it in 2nd gear, didn’t notice it in 3rd gear. My guess is that 2nd gear has the biggest ‘power band’ and that my injectors aren’t keeping up.

 

How old are the spark plug wires? I would suspect ignition leads/coils/or plugs under load like that.

 

Okay, well... the spark plugs are new. Proper dual electrode, the spark plug wires and coils were replaced by the PO probably 150,000 miles on those. Is there any way to check the coils individually?

 

Unless this little hesitation is driving you Bat Shit Crazy I would not worry I am sure changing the fuel filter service or new injectors new exhaust sensors all new coil packs >

Time for a engine refresh ??

 

only a little crazy haha thanks. I just like to have it dialed in, and I also like to show the other gens on the road why 1st gens best.

here one day (after I get the 01 put back together) I will get the whole engine cleaned up which will require valve cover gaskets, and when I do that, that’s when I’ll do the full engine refresh.

So you think that something fuel related is what it might be? My first assumption was fuel/ engine load related.

So maybe fuel filter would be a good thing to start with either way, since I’ve personally never done it?

could it have anything to do with the TPS? Or maF?
I’ve got an ultragauge, but I don’t see any gauges that would help me in this trouble shoot.

the only thing listed in the FsM matrix for hesitation is