Before I begin... I just wanna make it clear that I've put this question to other sites, and I'd just like to get as many opinions on this before I do anything. BTW: Since the engine involved is a LN2 (The most commonly found engine used in J-cars) and I've gotten much help with it here before... Despite it being in a S-truck... I figure that if I can get a clear answer anywhere about it, it'd definately be here!

Now, as I've said here before in other threads... On with the show!

Early last year I took ownership of a '99 GMC Sonoma to fill the void left when my '94 S-10 went down. I would've fixed the S-10 if I had a garage to work in, but I don't even have a paved driveway (You'll see later how this plays into my sitch). Anyways, I drove it until early summer when all of a sudden it died just seconds after starting, then failed to start in my driveway. While cranking it showed the same signs my '94 did (Like the timing chain failed). Given that I was familiar with the 100,000mi chain-failure idiosyncracy of the the Double-Deuce'd S-trucks, and the 'Noma had over 113,000mi when I got it, I figured "Oh great... Another failed chain!". When I finally got to replacing it, it struck me odd that the marks on the sprockets lined-up okay before removal ("Probably stopped the result of slap brought-on by the worn tensioner..." I thought). So I replaced it with a Cloyes timkin-link set & it ran much like it did before the failure.

Then one day, a heavy rain passed through the area overnight. When I tried to start it the next day it showed the same signs of inoperability it did when the chain failed. "Oh not again!" I exclaimed. To add to the fun, the starter (Probably factory, judging by the looks of it) failed to stay engaged with the flexplate ring-gear & had to be replaced. Since then, I've needed to crank it longer than usual o get it to start without kicking-back as the result of a backfire through the intake. If I don't, then I need to crank it even more extensively or do a clear-flood command to get it to start. Since then it'd start the same way but run rough for a a few seconds. Sometimes just after it started, sometimes after it started & ran for a few seconds.

Then this last November, heavy rains came & it shoed the same no-start troubles again! This really sucked since I needed to be somewhere & the other truck (Which was running fine, but had a broken exhaust) had a dead battery. So, I swapped batteries & took the '94. I let the '99 sit for a day with a charger attached, then tried it. It started & ran like flawlessly. But then, after a while of seeing use... it started the same old crap again!

Now mind you, I seldom used or even started the '99 last year because it had trans trroubles that negetively effected mileage (Leaked like a sieve, wouldn't hold overdrive above 55mph, convertor would unlock without any promptive action on my part). Early in November, I finally got it rebuilt & that worked fine... But the mileage was like as if I punched a hole in the tank with a screwdriver! I couldn't even get 17mpg.avg. outta it! And my '94 (Same engine, trans, gears, tires... everything!) got 24.7avg.mpg! since initially getting the '99, I've installed MSD coils & wires, a K&N replacement, and just last week... E3 plugs. It ran perfectly (Short of the trans woes) with the coils & wires installed before the first heavy rain, but now even with the K&N & E3's...

I've checked the connections at the PCM (Since it's so close to the edge of the hood) and they seem tight. Two people so far have said that it might be the crank-sensor failing, since that hapens at times on GM vehicles around 100,000mi. One has even suggested disconnecting the all the engine-management related plug (At the PCM & the sensors & actuators) and flushing the contacts with WD-40 'til it drips from them, then let them air-dry & reconnect them. Are any of these suggestions valid? Could it be just the cnk-sen failing & giving me all these headaches? Or is it something deeper... like the start of the dreaded "green-death" in the wiring of the PCM connected stuff? I'd sure like to know before I turn wrench #1, because I just 6" of snow in my area (Remember what I said about only a gravel driveway?) and I'd hate to start doing anything that's unnecessary or bigger than I can handle.


Go beyond the "bolt-on".

BTW: It never once in that time (Outside of trans-related codes) throw a light... Except once, just after the first heavy rain. But never since... And it just passed emissions!


Go beyond the "bolt-on".