Okay, make a "wa-wa-wa-wa-wa-wa" sound out loud and then rock your head back and forth at the same time...that's what it feels like in my '91 AWD under load up a hill once it's warmed up. Those are the constants in this issue. Runs fine cold. I can put it to the floor and it goes well when cold.
List of constants:
1. Vehicle must be warm before acting up.
2. Vehicle first did it under load, downshifting from OD to Drive on a hill (Yes, it had lots of fuel).
3. Tonight when it started acting up I put it in neutral while going about 80km/hr and depressed the gas pedal and it made the "wa-wa-wa-wa" sound, without any load!
Here's what I replaced in December 2011 that has anything to do with fuel or electrical:
1. All new spark plugs
2. Valve Cover Gasket
3. Fuel Filler Neck
4. (Catalytic Converter was replaced about one year ago).
5. Toyota muffler was installed in 2008.
This issue first started around the beginning of March 2012. I've now replaced in the last two weeks:
1. Plug wires with NGK brand.
I picked up a fuel filter today. Hoping that's an easy Re&Re in the garage. I'm wondering if this might be an injector issue???
Here's a link to a video I took tonight while driving up a long hill...listen closely around the middle and you should be able to hear what I'm talking about.
Any thoughts on this would be greatly appreciated. The van has 384,000 km's on it. I'd like to see it pass 500,000 km's.
Thanks in advance folks