I have a 1998 extended cab with the 2.2 L. Recently I have watched the voltage fluctuate when idling. I figured it was the alternator/voltage regulator going out after 102000 miles. Well sure enough just this week the alternator gave up the ghost. So I replaced it yesterday with a new Napa Gold Alternator. Everything seems good but I am still watching the voltage fluctate when idling. It happens regardless of the air conditioner being on or turn signals. I don't know if I should be concerned about this, could this be the reason the alternator went out in the first place? I would like to think that its just the guages having a little fun after 100,000 miles and not have to go on a electric witch hunt.

get a new batter no matter when you bought it if the alt goes it can take the battery and vise vers and check connections

check all wiring to the starter and from the alt make sure they are tight and don't have any frays in them

Just curious, how much did you pay for that NAPA alternator? Mine went out this week also (also a 98) with 120 thousand miles. It just looked too tight in there so I took it to the dealer to replace. Was it hard to replace?
It might make you feel good if I told you I had to pay $380.

I tried to get a cheaper one around $100, but no one else in town had them in stock and NAPA only had the most expensive one they sell. So I ended up paying 170 (lifetime warranty) and losing a little skin off the knuckles. As for checking the wiring, I was really hoping someone had a silver bullet fix and not an electric witch hunt. Maybe I will put the lifetime warranty to the test and see if whatever is causing the fluctation will cause another alternator to go bad. But on the other hand if I don't find the cause it may eat the engine control module next...

you don't have to rip the harness apart, check the wires where they are exposed for frays

Hey Lostaggie

I know your Pain, I am having the VERY EXACT same problem. Today my altenator when I out. I was able to go for about 3 months with the voltage guage acting up. PLEASE post your update. I would like to know what you have done to fix it. I hear a huming noise coming from the engine however I have not been able to indentify where it is coming from.

Well so far I have replaced the battery, and checked/cleaned the grounds and wires on everything that I can find. I haven't found a solution yet. My next plan of action is to start pulling fuses on non essential items, maybe further isolate the short that way. Other than that I have just been driving it. I will let you know if I find a fix.

P.S. I am thinking of taking it to a priest for an exorcism...