Changed 2 spark plugs...now very rough, can't drive

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Curt Brubaker

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Jul 22, 2007
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Location
Camp Hill, PA
Ok...I'm baffled, and without my ST for the day until I can get back to the garage to take another look. It's an 01 4x4 automatic.



I had changed all but 2 of the spark plugs and wires (the 2 last on the pass. side) about 2 weeks ago, and finally got around to taking the wheel off to get the other two tonight. The truck was running fine before, just doing maintence since I had bought the truck and never changed (truck has 71k on it).



Now when I start it, it's semi rough but you have to listen for it. However, put it in drive, and it stumbles all over itself and has no power. I pull each new wire off the coil pack seeing if it makes a difference. The middle cylinder pass. side dumps the idle even more, the last plug (furthest back) makes no difference at all. Ok, maybe it's not on the wire or coil pack right. Check both, their fine. Check spark at the coil pack, it's good, check spark at the plug, it's the same, very nice spark. So I pull the new NGK plug out (standards, no iridium etc). and pull one of the other side plugs that was in and working fine, and put it in that cylinder, and swap to the other side (Easier to get to). Same issue, pull the plug wire and no change in idle. GREAT it should be the spark plug. So I grab one of the old plugs, put it back in, and the same situation happens. So for good measure, I change the other brand new plug to one of the old ones, and still no change.



I'm totally baffled, and I let the truck idle for a while, checking all other hoses, connections etc. I spray starter fluid on most of the vacuum lines I could find in case I bumped something, but to no avail. After it idles for about 2 minutes, the whole idle changes, and it almost is stalling out just sitting there. I can hear the intake "popping" a bit which it's never done before. Now it has thrown a code but I don't have a scanner yet (trying to get one tomorrow) to see what it tells me. I tapped the IAC with no change just for shits n giggles. I also did swap the two new wires to see just in case I mixed them up, but I had them right, it got a lot worse and stalled out when I swapped them.



Anyone have a clue? Totally retarded to change to plugs and wires and now I can't drive the damn thing.



Thanks guys!



-Curt

stranded in central PA.:angry:



 
Are you sure you did not mix a wire up. Sounds like you got the last two wires switched.





Tom
 
I'm positive, and even swapped them hoping I was an idiot. I did one wire at a time however, so I was certain it wasn't the case. It doesn't idle badly, and most of the wires I take off the coil pack, have little effect on the idle, which is bothersom in itself.
 
Maybe you damaged the plugs/wires when you installed them. Have you gotten a Check Engine Light?





Tom
 
Yes after it idled for a minute or two I then got a Check Engine Light. The plugs I pretty much ruled out, as I have now taken both new plugs out, and put the old back in, gapped properly etc. Both ends internally look fine, as do the boots on the wires.
 
Hmmm... Taking the steps. New plugs & wires/old plugs & wires no change. If it isn't either one of those... I can only think of one situation that might be the cause of it. Perhaps some dirt or or grease got into the cylinder. I know its an off the wall deal. But seriously, I can't think of any other deal on to why it would be working like this.



Or check the compression of the cylinder vs one of the others.
 
I know your positive, but if it was running well before, then you either have a damaged plug or you have crossed wires.



I am sure this will be the issue once you find it.
 
I don't believe it can be a gap or bad plug issue, being that I've now removed both the new plugs, and put the old ones back in and have the same issue. I confirmed the plugs are correct, and I already have the others from the same set in the truck and running fine.



The wires are confirmed correctly.



I will check compression I suppose, the plugs are all the way seated in the head, and the wires are on tight.



Thanks for all the thoughts! Gotta be something stupid I bet.



-curt
 
I remember reading on this site that people have had trouble with different plugs. Usually they say to run only Motorcraft or Autolite..............just a thought
 
I have been known as the plug wire assassin. No way can I change a set of plugs without ruining at least two or three wires. For a few years I just had the shop put my plugs in but plug wires have gotten cheap enough that a whole new set costs less than the labor to change the plugs.
 
I think everyone here hit on the possible causes.



You need to go back to the basics. Put new correct Autolight plugs in every hole, making sure they are gapped and torqued properly (don't forget the anti-seize). Then, you might as well replace the plug wires as they are probably damaged from all the movement and activitiy.



This isn't rocket science. Go back to the basics and make sure everything is correct. Do each step correctly the first time and don't go back.



Yes, it very well could be the NGK plugs. Search the posts--most folks here have problems with any other brand of plug other than the Autolights that were made for it.
 
NGK plugs is you first clue. I have found out, by experience, that Fords run best on the plugs made by the company that designed the engine Ford.



First you need to get the codes pulled before you go further. If you have a misfire, it will tell you which cylinder it is misfiring in. If it says multiple misfire, I would bet it is your plugs and/or wires.



For my cars, nothing but OE plugs. I have had to do the job twice too many times because of all the hype around plugs that have some "improvement" to them that work no better or different than OE plugs do.





Tom
 
Last edited by a moderator:
I'll grab new plugs since they're cheap enough (although the original plugs back in STILL has the issue). I'd lean more towards the wires, at that junction, so I'll go buy another set.



I'll grab the scanner and see which cylinder it points at, then go from there.
 
Before you buy anything, pull the codes first.



Also, the plugs are not cheap. About $4.00/plug





Tom
 
NGK plugs is you first clue. I have found out, by experience, that Fords run best on the plugs made by the company that designed the engine Ford
Click to expand...



Sorry Caymen... I've read your previous experience posts on plugs and can't disagree with those. However, I run NGK's, and have for quite some time with absolutely no issues. I beleive the plugs are TR55's. Moreover, Curt was running 4 NGKs with no issue as well.



Curt I wouldn't be so quick to blame the plugs due to brand, at least, not in this case. My guess is that you have a wire issue. I've crossed wires in the past and had similar results to what you described including throwing a code. Which code will be the kicker here and getting a reader will be your best bet. However, if it were me, I'd be talking a close look at the wires.
 

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