Please help!!

I would greatly appreciate any sage wisdom offered about my current issue with my daughter’s 1999 SR5 4WD 6 cylinder.

About a month ago we got a check engine light for a misfire of cylinder 6. Car ran well just had a slight shudder upon warm up.

Because I’m lazy and not incredibly electronically capable and the car is 25 years old, I decided to change out coil packs, plugs and wires along with pcv valve to see if that was the issue.

Problem apparently solved!! Ran great afterwards. No issues. No shudder. Good acceleration. No check engine light. Probably for about 100-150 miles.

Today, ran great made two stops on the way home and on the second stop - after starting to go home. Big shudder, obvious misfire issue - limped into parking spot. Check engine light on. OBD’d it - misfire cylinder 6.

What is going on?????!! Why would it run so well then crap out? If it was a valve or cylinder ring or anything else mechanical, changing out coils, spark plugs and wires wouldn’t have made a difference in performance.

Injector?? I’m at a loss.

Any help or ideas would be so appreciated. I will send a case of great red wine I made to anyone that solved this for me!!!

 

Wow! I did the same thing. And then it was an injector too.

 

Have you checked the wiring for any rodent damage?

 

Thank you SR5 Limited!! Fingers crossed and Steelevo - no apparent rodent damage.

 

Just in case you used aftermarket coil packs and got a bad one, did you try swapping them around to see if the problem follows?

 

Thank you Daddykool - yes, they are quality Denso OEM replacements. And - since it ran well for 100 miles I don’t think it’s a faulty coil. Who knows? Stranger things happen I’m sure…

 

The suggestion to swap the coil packs around is easy and tells you a lot.

It's worth a coolant test for exhaust gases. Try and rule out a pesky head gasket. If it's not a head gasket, it's looking more like an injector. I'd run it for a while and pull that number 6 plug again and see what she looks like.

 

Thank you negusm!