89 Jetta GLi 16 V with a ...

89 Jetta GLi 16 V with a occasional miss and hesitation . My guess is that it occasionally runs only on 3 cylinders? I thought it was a plug wire, but, for what it's worth, (at idle) I can pull a plug wire and lose RPM, reinstall it, gain RPM, -repeat on each cylinder; the wires seem to function ok. One, though, is missing the rubber insulation nearest the plug end---can that cause scatter voltage issues? My auto parts store wants $120.00 for a new set of plugs. I'll wait to buy them after I have tried less costly diagnostic procedures :)

Air filter ok. Plugs clean. Distributor cleaned and checked.

I'm prepared to change the fuel filter since I have no idea if it has been changed in 230,000 miles. Don't know what symptom an old, dirty fuel filter will cause, but figure it's long past time for a new one...I'm also curious to see if any crud may come from the fuel line near the filter, too!

? Is there some sort of maintenance for the fuel distributor?? Can you recommend a gas additive?? I've used Berryman (sp?) and Seafoam (or something like that- it works in both crankcase and gas tank). Some improvement noticed.

best ones! daniel

"You're not supposed to be so blind with patriotism that you can't face reality. Wrong is wrong no matter who does it or who says it." ...Malcolm Little