I put new spark plugs and wires in my 96 3.0L Ranger a few weekends ago. Gapped the plugs to .045. Recommended was .042-.046, I think. Everything was fine except for slight pinging under heavy load and low RPMs with the a/c on. So, I decided to widen the plug gap to .050. I figured I'd start wide, and work it down. I drove it around a little and it worked fine. No need to back it off. A day later, I noticed it was misfiring when accelerating with low RPMs. Last weekend, I regapped the plugs to 0.47. Now it totally misfires even when idling. It seems like some cylinders aren't even firing. The CHECK ENGINE light started flashing, then went steady. Argh!!! I should have stopped the first time around.

My guess at this point is I broke some of the wires or plugs. This weekend, I plan on checking the resistance on each wire to validate my theory. If the wires check out good, is there a way to check the plugs? Should I just get all new wires and plugs again? Should I just give up and take it to a professional?

Thoughts anyone?

Thanks.

 

What kind of wires did you use. Hate to brand knock but the wires you buy at A-Zone tend to be junk. I know this from past experience. Well ok maybe not junk ..... how about of very low quality. That seems not as harsh. Are you sure you put the wires back on in correct order?

 

Yes, they were the wires from AutoZone. I did check the resistance on the wires before I installed them. They had less resistance than the original ones. Based on that, I assume these were good wires.

I was pretty careful about getting the right wires with the right cylinders. I followed all warnings about only disconnecting one wire at a time.

Thanks.

 

are your plugs w/in the correct temperature range? also, i wouldn't rule out bad local fuel supply, prices climb so vendors tend to buy "cheaper" quality fuel. and if that's the case your o2 sensors may have been damaged.

 

OK, I am the cheap guy. Take an old plug wire (I hope you didn't throw them out) and replace the new wires one at a time with the one old but good wire. You may have two or more bad wires. Takeing wires on and off causes them to go bad. If you set the plugs gap and there is not some carbon or other object across the plug gap. Consider the plugs good or put old plugs back in for questionable plugs.

If all this fails gap the plugs and check for cracks in porcilen insulator. Then go buy a set of quality wires and check a book and make sure they go to the correct places.

Sounds like you created 2 or more troubles and that gets complicated. An old fashioned timeing light can tell you if a plug wire is good (firing). These old lights use only two wires and are pluged in series with the spark plug. These old lights are usually cheap to buy ( less than $10) if you can find one.

 

I tested each spark plug wire and found them to be around 5 k/ohms, except for the wire on plug #3. That one measured 10 k/ohms. So I replaced the 7 mm set from AutoZone with an 8 mm set from PepBoys. The new wires measured between 1 and 2 k/ohms. I had difficulty feeling the "click" when installing the wire on plug #1. I noticed the porcelain insulator was cracked! The rest of it crumbled when I was removing the plug. Luckily I already bought another set of 6 spark plugs. Everything works fine with the new plugs and wires and I'm not gonna mess with it again!

Thanks all.