02 chevy 4.3 "random misfire"???

[Jay@Lamotta]

A buddy of mine has a 52k 2002 4.3 powered truck, it misses under load. With a scan tool you can watch it miss on all different holes. The truck also will shut it self off and will not restart for around ten minutes. It has a new GM cap,rotor,wires and plugs. I have been told that these trucks have a problem with the distribitor?? Anyone out there been through this? Thanks in advance, Jay

[cobra1]

Originally Posted by Jay@Lamotta

The truck also will shut it self off and will not restart for around ten minutes. Thanks in advance, Jay

sounds like the ignition module heating up to me.

also, check the fuel pressure. before starting, while running, and after it shuts off and wont restart for ten minutes. fuel pump may be getting hot and malfunctioning. check a Haynes book or Chilton to find out what the pressures should be.

[kevine323]

My 2002 Silverado was also having the same problem so I took it into the dealership and they said it was the distributor cap. When the AC was on , the hose that runs above the distributor cap to the AC was dripping on the cap and corroding it. The dealer said that they have had this problem before and they replaced the cap and insulated the hose. Everything is normal now.

[sweninge]

Originally Posted by Jay@Lamotta

A buddy of mine has a 52k 2002 4.3 powered truck, it misses under load. With a scan tool you can watch it miss on all different holes. The truck also will shut it self off and will not restart for around ten minutes. It has a new GM cap,rotor,wires and plugs. I have been told that these trucks have a problem with the distribitor?? Anyone out there been through this? Thanks in advance, Jay

I think I know what it is. I have the same problem and it took me months to figure it out. Doing this simple test will save you a lot of money and aggravation. I came up with it on my own and it works great.

Take a zip tie or small bungy-cord and hook it over the distribitor cap so it is basically pushing the cap down on the distributor. Clear the code. Drive it around under different speeds. If the misfire is gone you have found your problem.

Either you distributor housing is cracked or screw hole is stripped where the screw goes into the mounting hole or the cap is not on all the way. Believe me, it doesn't take much for the cap to be a little lose for the random misfire code to activate.

The fix is either replace your distributor housing or tighten the cap. The reason I know it's probably you cap is because you just replaced it and the problem started. Right?...Trust me. I went through this and GM has cheap plastic distributor houses on there trucks to save $$ and weight.
Cost cutting bean counters at work once again.

If this test doesn't work then its electrical.

[tim shady]

Originally Posted by sweninge

Either you distributor housing is cracked or screw hole is stripped where the screw goes into the mounting hole or the cap is not on all the way. Believe me, it doesn't take much for the cap to be a little lose for the random misfire code to activate.
The fix is either replace your distributor housing or tighten the cap. The reason I know it's probably you cap is because you just replaced it and the problem started. Right?...Trust me. I went through this and GM has cheap plastic distributor houses on there trucks to save $$ and weight.
Cost cutting bean counters at work once again.

agreed. you might not even be able to see a crack or a stripped screw... and its definitely worth a shot.
I just purchased an 02 1500 4.3. A couple weeks after I got it, it wouldnt start... at first. a week later it did it again. and then the next day as well. The dealership was stunned.. After ruling everything else out, and going through a couple weeks of waiting, they found it was the cap. It looked absolutely fine (maybe even new?), no cracks at all that I could see, no stripped out screws, and it appeared to fit tight. Well something was up cause it got the slightest tiny bit of moisture in there and then it wouldnt fire.

[markqc]

Check out my post on this link
http://www.automotiveforums.com/vbul...ht=engine+skip

Your 2002 may have the same distributor vent hole that needs to be blown out or remove the vent screen.

Good luck,
Mark