3400 cuts out WOT

[randomBullets]

Ok, I have a '03 Venture w/3400 w/178K miles. I've got this weird WOT issue. While in park, pushing accelerator to the floors causes the engine to do this weird up and down rpm jumps. It's not hitting the rev limiter it's slower than that, it's almost like the fuel drops out or something. The only thing is I tried to do it under a load and it's fine, I mean it's a van so it's a little sluggish on dead stop acceleration anyway, but it's not doing the same thing as far as I can tell. The idle is around 700/800 according to scanner I have, but it's weird "feeling" like the entire van has this weird "shake" to it, I can feel it in the steering wheel and can see the passenger seat shaking.

Here is a list of stuff I've done to the thing in the past 6months but after doing each of these things this symptom didn't happen, it started really out of now where semi-recently.

Lower/Upper intake gaskets
spark plugs/wires
fuel filter
air filter
2-oil changes
rebuilt alternator w/new battery

I have a feeling I need to hook it up to an O-scope to see the waves I'm sure I could pinpoint something that way, put I don't have the money to get it done, so old school diagnostics is what I'm left with.

I feel the first thing to check would be the fuel pressure. What do guys think? Has anyone experienced this?

My other concerns with this motor is loud tapping and I can't help but here a slight knock on the bottom end. I think maybe she's down for the count, possible I'm up for a 3500 swap? Or not worth it?

Thanks for your help in advance.

[1QUICKHATCH]

what rpm dose it cut out in park? most fuel injected cars have a park/nutral revlimiter set around 3-4000rpm. Are the spark plug wires in the correct order?

If the van is in good mechanical condition, body, brakes, tires, transmission... I would say go for the 3500 swap!

[randomBullets]

Hmm, I'm not sure what rpm its cutting out at but, past experience with rev limiters it was like a high fast in and out. This is like a waaah-waaah sounding thing. Lol that's funny trying to type sounds out. I say wot but I can make it do it at part throttle like 3/4 maybe.

Yes, I'm fairly sure wire are right, would that give me a DTC? I'll check again to be sure.

I'd love to give a 3500 a fair shot. I found one with 28k for 750$ with accessories, sure is tempting but I'm not sure about OBD-II and making that right. But that's another thread.

[Ravager]

Mine Does the same thing!

Strange thing to say the least.

Have you figured it out yet?