germantoy

Perfect vacume, same boost as usual, new o2, clean iat, clean air filter, recent fuel filter.

So when im on it full throttle it will hesitate a little then go. If i stay on full throttle is sounds like a supra breaking up when drag racing (best way i know how to explain the exhaust noise) there is no detonation sound so im confused and no check engine light ???

Mike Desi

Also check your plugs and make sure they are snug.

elijahallen

go get a couple gallons of toluene and mix up a batch of 98 or above octane. I did this when I was having a similar problem and it fixed it right away. Be careful though the night I did this was the night I toaled my car. To much extra power to deal with I guess.

Elijah

TripleBlackS6

As per my recent experience, if everything you try fails then clean the POS connectors :-)

QU4TRO

... I'm pretty sure you know more about this stuff than I do, but as I understand it, (especially on modded 20V's) there is an issue with the plugs actually backing out, or in the case of my frineds S6, blowing out completely. Also, it couldn't hurt to check the wires for arcing, and the fuel accumulator (or pressure regulator, whatever they call it in our car) for a leak, but you would have noticed that already, what with the smell and all.
Hope you find the problem soon.

AntiSocial

I already did the #5 coil and it's a bitch to do since there aren't connectors for it like on the newer Oodi's.

I say replace all 5 if you can swing it. Or try out the ignition solutions replacement coils. You really need a tube header on there.

AZSantorin

Swap in an ignition pack (the 20vt turbo aluminum thingy... the name escapes me now) from a known good car. Disconnect at the power output stages and connect the donor.

Ignition problems (arcing to the block, bad plug leads, weak coilpacks) with the plug leads or coil packs can be ruled out this way.

Emerald-UrS4

I posted this a while back... try it out it might help determine which coil is going bad without dumping $600 bucks on a whole new set !<ul><li><a href="https://forums.audiworld.com/s4s6/msgs/28698.phtml">https://forums.audiworld.com/s4s6/msgs/28698.phtml</a</li></ul>

HarryBauls

I couldn't find a spark gap tester... so I made mine out of a 2 pieces of wire and the plastic cap off a spray can.

Placed one wire on the coil and grounded the other on the block. I kept gaping the wires out farther until the point a coil I thought was good wouldn't arc (about 3/4 of an inch). I then moved from coil to coil until I found the one which wouldn't arc at this point (#3 in my case - it would only arc at about 1/2 an inch). Replaced this coil, high boost stumble gone, and the car runs great.

Another symptom of my bad coil, was that it would eat plugs, and there was a bunch of blow through on the plug crusting up the connector and coil.

Took 30 seconds to make, and 15 minutes to test.

Cheers.
Dwayne
94 S4, T04e-50, FMIC, WI, suspension, big brakes, boost controller... + other stuff

Emerald-UrS4

Way to go !!! I applaud your MacGyver'ness...