So about 6 months ago my truck started acting pretty shakey, loss of power, low idle, etc. So I replaced the fuel filter (it needed it anyways), cleaned the air filter. The problem still continued to happen. Some days worse than others, some days made me scared to drive it.

So I finally went to the local auto parts store and had em check the code. Cylinder 5 misfire. I replace the plug since it's the cheapest thing. Still does it. So I replace the coil since it's the next cheapest and logical thing. Still happening. So I am thinking that means probably the injector? Cause I am still getting the same error read at the parts store. On it's bad days the truck will shake pretty bad and the check engine light will start flashing at me. Been going on for about 6 months, but since I car pool it's not a daily driver right now.

Any ideas or advice would be appreciated!

Thanks in advance
Derek

 

Sounds like an injector 100%. I would replace asap.

 

Swap the injector with another cylinder if the miss move replace the injector if it dont do a compression test.. if it does replace the injector.. I would also throw in a nice treatment of techron..

 

Ok, thanks! Just took the old one out and got another one on order. If this doesn't fix it, then I guess I'm looking at much bigger problems with the compression issue.

 

Swap the coil with a known good one before moving on to a compression test. Confirm the new coil is good first. Unfortunately, there's allot of those that are bad right out of the box.

C- testing procedure in sig below.

 

I'm agreeing with with JBrew.. Don't trust that the C.O.P out of the box, as they aren't necessarily all in, working order!
I have a 2001 w/ 4.6 L engine. I was throwing a code for #5 and # 6 Replaced the plug on 5 and 6 (then replaced all 8 with Iridiums,later) and when pulling the plugs I found a oily mess down the cylinder plug wall and aspirated both and installed two new COP's cleared codes and within 3 days I had a #5 code again. Pulled the COP and the tube was oily again. Found that the bolts needing tightening/torquing around the thermostat hose at/close to # 5 cylinder, had allowed antifreeze to seep along the right bank of plugs and caused the shorting /missfiring and code. The C.O.P I had just changed was (I beleive) acting up and I replaced again and no issues since.. except a P401 code which I replaced the DPFE Delta Pressure Feedback EGR and she's been purring like a kitten for over 4000 KM and fuel economy has shot right up!!