Performance Loss 2 Mos After Plug Change

[alvocado]

I did my first plug change 2 mos. ago and installed Delco Iridiums. Immediately after the change, the truck ran smoother and had more power under acceleration. The performance lately is noticeably degraded especially under acceleration up hills. I cleaned the throttle body intake and replaced the PCV valve while under the hood today but no difference. It's not horrible but definitely noticeable. Since I left the original wires on and hit 90k miles this weekend, is there anything I should check before installing a new set? I know there is a risk that the wires can be damaged during a plug change but I usually notice an issue immediately if this happens, not 2 mos. later. Can the wire damage take some time to manifest itself?

[papastoy]

Could it be the switch to winter blend gas or a bad tank of gas? I'd try a bottle of Chevron Techron fuel system cleaner first before condeming the wires and see if it helps.

[C & A s Dad]

Try the Techron at 1 oz per gallon and you may need to do this for 2 tanks. However, I am going to bet you have wire issues. I know our Counter Pros do their best to sell a set of wires when they sell the plugs but not everyone will do this. Many times, they find the customer coming back later with wire issues. The wires are so easy to damage when trying to remove them.

 

Hope you find your issue.

[alvocado]

Could it be the switch to winter blend gas or a bad tank of gas? I'd try a bottle of Chevron Techron fuel system cleaner first before condeming the wires and see if it helps.

 

The performance loss was evident during an entire 600 mile road trip this past weekend and I've never noticed a change when the gas blend shifts for winter. Since I'm approaching 100k miles, it might be time for a wire swap anyway so I'll order a set. I wasn't too thrilled to find that my local dealer wants $114 for a set and couldn't tell me which length wires I needed based on my VIN. Apparently there are two lengths depending on the ignition manufacturer and I was too lazy to pull the plastic covers off the engine to look.