I have a 1995 vw cabrio, 5 speed manual transmission and I am having a problem with the dash, car starting, bucking and stalling. I replaced the negative battery cable about 2 weeks ago because the old one was was badly corroded and my tach and speedometer would work intermittently (when it doesn't work, the needles usually bounce and I have replaced the cluster 2x's with no change). After the neg cable change, the car seemed to start as if it had more power (but the prob with the tach didn' t improve) but I noticed that about 1-2x's per every 5 starts, the car wouldn't start (no dash lights, no click, nothing) but when I turn the key again, the car would start as if nothing happened. I have rechecked the battery cables and they are on tight, with no corrosion. Over the past 3 days, I began to notice that the car "bucks" when I am on the freeway going over 55 mph (I haven't noticed this during street driving but I am constantly getting caught at lights). It does this about 2-3x's a day and 2 days ago, the car actually cut off at a light (but it started right back up). From a visual inspection, I can see that the ground strap to the cylinder head is badly corroded and the ground to the coil is just as bad. I am going to replace these this weekend and have my ignition coil checked but aside from that, is there anything else that I should check/test/ replace?
FYI...I have already changed the distributor cap, rotor, spark plugs and wires about 2 months ago.