1997 - V6 3.8L - ~99k miles

I sea foamed the car a little while back and shortly after this stuff began. I did accidentally run the car completely out of gas after sea foaming as well.

It started off as light random bucking at idle. It progressively got worse. I had the spark plugs swapped but it didn't really do much. The car initially threw a misfire code but then nothing, no codes just idle bucking and while cruising on the highway you could occasionally tell where it felt like it was slipping in power. But gas mileage oddly enough was right around what would be expected ~24mpg average from mixed highway/city driving.

Today it is just brutal, I don't think you can really even drive it. At idle it runs almost like a diesel, voltage drops and it bucks and kicks around. It threw a P0300 (Random Misfire) and PO336 (Crankshaft position sensor fault) and the SES light was flashing the entire way home.

Any help?

 

Did you look through the stickied misfire thread?

 

Yea, I was reading it. I don't know though, because my gas mileage really wasn't effected.

 

That happened on my 3800 SC, it turned out to be a broken pin on the ignition module/coil pack. I had misfire on #4 that would come and go. Maybe you could try a known good coil pack to eliminate that or have it tested if someone around you can do that.

 

Ehhhhhhhhhhhhhhhhhhhh. I hate whoever designed the plug wire configuration on these cars. I can rip down and rebuild a big 8 cyclinder engine in a corvette, but changing plug wires on this car... FFFFFFUUUUUUUUUUUUUU.

I propped the car up but I could barely get to some of them. I'm calling a Chevy dealer to see how much it will cost to rape me. The ignition modules need to be changed too. I cleaned off the connectors and one had rust fall out of the plug when I pulled it off and the electrode was all corroded. One other was similar but not quite as bad. Hopefully that solves my problem, I don't want to dump a bunch of money into the car cause I just need to sell it in a few weeks when I finish rebuilding my other car. Figures they're both down at the same time.

 

you should have room to work on a 3800 in the camaro. Try it in a fiero now that's a good time

 

The dealer never called me back, so I said screw it and did it myself. Swapped the plug wires and ignition boxes. Sparkplugs were already swapped ~1000 miles ago. Runs like new, even the slight hesitation I've had for quite some time when accelerating hard it gone.

It was still a pain in the a$$ though, took ~3 hours.

 

If you think the 3800 is bad...

The LT1/LS1 is worse when it comes to all things spark plugs...