Seriously bucking under full throttle

[Mad Cow]

when my VAF was bad it was black around the edge of the sparks and grey on the electrode...
I think it's when you've got spark and fuel... but not air.

I think that means it ran rich enough to blacken the whole plug, but then it ran normal or lean and the carbon on the electrode got blown off or something.

[wytbishop]

Reading this thread has convinced me that my VAF is starting to go. My idle is really weird. Sometimes it idles perfectly at 750. Then after a while it goes down to about 550 and sounds like its going to bog out. Then sometimes it rises steadily up to about 1600 and then cuts down to 900 abruptly then uuuuuup, then cuts to 900...then uuuuup....then cut....it's really strange.

I'm starting to think VAF.

[Daninski]

You certainly have your ups and downs. lol

[wytbishop]

Booo...hissssss

[_-Night-Shade-_]

Idling is different though, cause then it could be your IAC.

[wytbishop]

Yeah I've been working on that too....it's a PITA figuring this crap out.

[Daveb]

I keep answering... We are running out of advice.

I m wondering about fluids, it sounds like a longshot, hows your antifreeze & oil ? going down ? any foam in oil (like on cap?)

Pop # 1 plug and put a new one, drive her for a while. let us know. You mentioned you forgot to check your plugs, maybe they have 2 seperate conditions. You have been messing with so many different thing you may have dug yourself into a hole.

The most obvious problem is usually the problem

[Mad Cow]

There is a small antifreeze leak around the water pump but I always top it up. The oil level is fine, and there's no mixing of them so the head gasket's fine. And I did recently change my plugs, and I didn't touch anything after that, so I'll check them today.

[RX8SE3P]

I've got a crappy bucking happening at about 600-2000 rpms. Pretty much in 1st gear. Fees like no power then lots of power, then no power and lots again real quick and makes it a b---- to take off.

If I rev up a little and ride the clutch just a little I can stop it from happening, if I take off normally and I'm rolling at like 3kmph and just try to accelerate hard, I get the problem. Wondering if my engine mounts are completely stuffed and the engine just is not holding in place. If I floor it in 5th gear whilst going 60kmph I get massive bucking, like the engine is moving heaps. I should not have used my old K8 mounts that are not filled....

But yeah, I changed my fuel filter, I changed my plugs, tried different disty, tried different VAF and ECU. Still the same. Perhaps engine mounts? If I take off slow as possible I get no bucking.

[wytbishop]

The online manual has a fairly extensive troubleshooting section. It describes common issues and provides a logical path for testing and diagnosis. I think that most people, myself included, just don't have the patience to work the troubleshooting system. It gets pretty tedious after a while.

Start at the beginning. Test everything in order as described in the manual and my guess is you will be able to isolate the problem. Start on F2 140 and go. Even just reading it will tell you a lot of the things you need to be thinking about.

[Daninski]

Jeess I didn't think of this earlier. I had a bad coil modual in another car and it did exactly the same thing. I'd could be driving along but try to use anything more than just enought power to go and it would buck. Like I said I was getting spark but I think it was arcing inside the disty.

[Mad Cow]

I did the HEI+external coil mod so I doubt that's the problem. Although my plug wires may have gone bad in the winter because they went through a ton of freeze-unfreeze cycles.

[Daveb]

1 winter shouldnt wreck your wires, do resistance test on one if you havent put new ones on yet. I found a nice set in scrap yard for my GS, just took my little tester with me. I m on a budget & locals wanted $350 for a new set.

[Mad Cow]

What's the resistance/foot or whatever for blue NGK wires?

[tineke]

My 96 1.8 v6 k series auto has the EXACT same bucking issue from 0-4000 rpm's,and first gear would feel sluggish sometimes,.then GIVE ER when she was ready,it would catch me off guard. I let it go on for 4 months procrastinating about the problem and when to fix it ect. Now the car is in the tranny doctor office getting looked at because for the last week,the car also began to shift slowly like it was thinking about shifting then would shift. Reverse feels in neutral then gives her all by herself. It would sporatically redline to 8 rpm's say if I was turning a corner fast or punched on the gas to merge into traffic,when I let off the gas,problem stopped of course.
The car just had an oil and tranny fluid change on the 6th(I think they put the wrong fluid in my car). Prior to that the fliud was continuously topped up with dextron 3.
There is a tranny fluid leak that is sudden and major.
Today on my way to the tranny doctor,it wouldn't get out of first gear and the rmp's were extremely high and it sounded like the engine was going to blow up , so I eased off the gas and barely applied any pressure to the gas.I couldn't go faster than 10km/h all the way to the shop.
Half way to the shop I turned around to go home and put more tranny fluid in, and headed out to the shop again..the problem didn't go away.

Get er looked at before you run into something like this.