I have a 2001 ram 1500 with the 5.9. I was driving to work the other day and it suddenly started missing really bad. I stopped at advance and had it coded. It is misfiring on cylinders 1, 7, and 8. It also coded that #1 injector was stuck open. I changed the distributor cap, didn't help. Checked the plugs. They are getting fire. Put half a can of seafoam in with about 5 gallons of gas and let it run for 20 minutes. Still missing. It misses at idle and when driving. It smooths out a little at high rpms. Any suggestions are appreciated.

 

Did you change the rotor as well?

Might try routing the wires per the TSB. (its in the faq section.) See if that helps.

Need to find out what's going on with injector 1 as well.

 

Yes i changed the button

 

Make sure the wires are routed per the tsb. This is pretty common on these trucks. I'd also check the coil. You can buy tools that you touch to the plug wire to see if they are getting spark. This might be helpful as well. Since you're getting an injector code, I'd be tempted to check all injectors as well, although it's odd to get a misfire on more than one cylinder if only one injector is bad.

If you check everything and still can't find it, these trucks are known for having cracked heads which can cause a misfire that is is hard to track down.

 

Isn't the map sensor known to cause random missfires?