Help!! B6t stumbles

[fitsbain]

My B6T (still in the capri till I solve this, then on to the festy) has a throttle related stumble. If you ease into it from any RPM, it will accelerate (in neutral in the driveway as it has absolutely no brakes). However if you are more aggressive with the throttle, it will stumble (miss-fire?). From a higher RPM it will stumble and then recover and rev. Once it is revving (RPM increasing rapidly) all seams fine. Does brake up a little when you take your foot out of it and the butterfly closes.

Its got new plugs, wires, cap and rotar, air intake, new vacuum lines (most places, remaining look good), timing set to 12 (down from 22 ish before I touched it). Idle is at 850.

SO?

What do I do now?

And Thanks

[FestYboy]

Check. For spark leak at the coil tower.

[fitsbain]

pulled the bumper and the intercooler. IT blows free. Reinstalled

New coil coming tomorrow.

[fitsbain]

installed new coil, set TPS to 660 with throttle closed

No help

No wideband, nose says rich.

[Icedawg]

Check fuel pressure under load. I had a similar problem and the pump passed standard checks, but when I floored it the pressure dropped to less than 20 psi before recovering. A new pump fixed it.
Check air flow through fuel filter, when you blow through it there should be almost no resistance. Plugged filters can do this.

[Advancedynamix]

How old is the gas? They don't like old gas. If it's been sitting more than 6 months without a fuel stabilizer than you may have bad gas in it.
Also, did you wash the engine or has it been rained on? Water gets into the spark plug holes on these engines and causes the problem you describe.

[shadetree]

^ yurp !! Most likely the issue .. This guy knows a thing or two , cause he has seen a thing or two .

[fitsbain]

tank was empty

put in 5 gallons

havn't checked the filter,

no water or wash

[Advancedynamix]

How long have you let it run? The fuel pressure regulator may be varnished from sitting. How long did the car sit empty? It could be a clogged filter too. Misfires (even lean misfires) produce a fuel smell that could be confused as a rich condition.

[Advancedynamix]

Is there a critters nest in the airbox?

[fitsbain]

There was a nest, I did a cone filter.

probably 30 to 45 minutes run time. Put 5 gallons worth of Lucas injector cleaner in prior to the 5 gallons or gas.

Took advise and pulled the fuel filter. I can blow through it in the proper direction (the way fuel flows), but I think its harder than it should be.

So I'm grabbing a new one. AutoZone has it for $25.

[Advancedynamix]

Check the ignition timing and the cam timing. Also, the bearings wear out in the distributor on the b6t and cause the distributor shaft to wobble and do funny things. It's easy to check. Pull off the cap and try to wiggle the shaft. Also, check really good for air leaks. A cracked vacuum line or intake tube will cause a stumble.

[fitsbain]

Pulled the timing cover, crank to cams are good.

Pulled and plugged the volume line to the dizzy. After warm and at 850 idle, timing was 22 ish.

Set to 12. Reved and watched the mechanical advance happen. All looks good.

Filter in tomorrow if I get time before boyscout camping trip.

[fitsbain]

changed the filter

No GO same stumble as before.

What does the solenoid on the vacuum line between the intake and the fuel rail do?

[Flyin4stroke]

Make sure your flappy thing (vaf) is working right. And not clogged with debris. Anytime I had b6t issues it was spark related.