Engine misfiring cylinder #3
I have run into an issue with these engines miss-fireing on #3 before.
You may want to have you tech check the miss-fire count for #3 & #7 on his/her scanner, THe distributor cap on these engines is made so the spark for #3 crosses over the path of #7 & they sometimes mix & become one. What happens then is they may be fooled by a spark coming through the wire if on a test lead but won't send the spark to the cylinder. The spark always goes to the easieat place so when cyl.#3 is ready to fire it is easier for the spark to go to #7 & vice-versa, So you tech will see a constant miss-fire on #3 & an intermitant missfire on #7. they can ceck the cap by pulling #3 plug wire off the distributor cap while the truck is running & there will be no spark, if he puts #3 back on & pulls #7 off there will be no spark there. the computor will only set a #3 miss-fire code because that is the cylinder that miss-fires the most.
If they find that is O/K you will want to have them do a compression test. If they find the compression is conciderably lower on cylinder #3 than the rest the camshaft theory is plausable.
The next step will cost you some money but it will tell you if you have an injector issue. You will have to pay you tech about 3.0 hrs to do this & you can just have them replace the #3 injector & hope it works. But they are around $200.00 rebulit so thats alot of money to throw at a hope. You'll need to get them to swap the #3 injector with the injector from one of the other cylinders then run the engine. if the miss-fire moves to the other cylinder you know you have an injector issue.
I hope this helps, Good luck, please let me know how you make out.
Mar 19, 2009 |
1999 Chevrolet Tahoe