last Saturday (May 17th) I took my spark plugs out, cleaned them, and checked the gap. after doing that the truck runs real rough now at idle. I only drive it twice a week, to school on Friday and church on Saturday (it just so happens that I didn't drive it to church that evening). well my dad drove it 3 days later on Tuesday to a school band concert. he didn't tell me that it drove kinda bad though. so on Friday morning I got in the truck started it (it always runs rough in the morning since it's not warmed up so I didn't notice anything unfamilar). once it gets warmed up it runs nice and smooth. so we get in and drive to school........ after school (90 degrees F or so) I start it and it is running real rough so I just keep my foot in the gas pedal a little bit so it doesn't stall at the stop sign. now I drove to get the truck inspected. after the inspection I got in it and drove home, it was still running rough and it felt sluggish on the road at 60 mph. I told my dad when I got home that it seemed to be running bad. he said, "Yeah, I noticed that on Tuesday. you probably just didn't put one of the spark plug wires on right and it's not touching right or something."

well I walked out to the truck and undid the wires one by one and made sure that they were on "good".

I don't know if this is the problem or not but when I pulled the spark plug wires off I sprayed a tiny bit of WD-40 on the inside of the wire so I could get the wires on easier this time.

or I don't know if one of the spark plugs isn't screwed in all the way.

if y'all have any answers for me I would appreciate it very much. thanks

 

did you try and tighten all the spark plugs? that is your best bet. check to see if your truck is skipping a beat. by that I mean it sounds like a cylinder is not going. I dont know if you know how to check it but your best bet is to make sure all your wires are plugged in tightly to the distributor cap and to make sure all your spark plugs are nice and snug and that your wires on them are on them good. if it is still doing it, maybe a bad wire or plug, its often best to just replace the plugs not clean them, its not too expensive. The wires could be going bad. that is the first thing I would check do to that is all you've done to your truck. is it running at high rpms? or more like its skipping?

 

no I did not check if all the plugs are tightened down completely.

I will check and see if my wires to my dist. cap are on good, even though I didn't take them off anyway.

I know that I probably need new plugs anyway so I'll probably go get some.

and no my truck is not running at high rpm's. it's more like it is skipping.

 

ok if it is skipping you have A. unplugged wires (or loose, my suv was skipping randomly and I hadnt replaced the plugs but one on the dist. cap was loose anyhow)

B. loose spark plugs

C. bad wires

D. bad plugs

just check the wires and plugs, its most likely what it is.

 

I'm thinking that it is probably the plugs cause when I took them out and wire brushed them I knocked a little bit of rust off of them, so obviously that means that they were in there for a while. the dealership (mom and pop place) I bought the truck from, I think that the truck was there for a while and the PO was the one that fixed it up.

 

when you replace them you'll get a whole lot of power back into your truck.

let us know if you get it corrected.

 

oh do you recommend that when I get the new plugs to get the number that is on the tag on the side of the engine?......BSF-42

 

no if you go to NAPA or Shucks (it might be checkers or kragen by you i dunno) you can tell them you have a 79 F-100 300-6 and they will have all the plugs you need at different prices and performance you can choose what you want. I usually go middle of the pack, and platinum but right now my truck bed is crunched and I am unable to drive it lol.

 

that's not good about the bed, I sorry to hear that. well ok I guess I'll go to NAPA 'cause that's my mom's relatives that run the place (I might get the plugs for little or nothing). oh and thanks for all the help on these 2 threads that you are helping me with. maybe one day I'll be able to pass this knowledge on to someone else.

 

well I am only 18 I joined this forum when I was 16, and have learned a lot so I enjoy helping others out cause I've been in your shoes not knowing a lick of anything. between this forum and my dad I have gotten a lot of information. Glad I could help.

 

that's great 'cause right now I'm 16

 

Check your plug wires at night and look for arcing under the hood next to the head by each plug, verify each plug wire goes to the correct plug, firing order is 1,5,3,6,2,4.
Also check your coil wire, make sure it is good, and if you are getting a deal on the plugs, and you aren't sure when the wires were last rplcd, might as well do the plug wires/cap and rotor all at the same time, just easier since you are already there buying them and doing it. Possibly when you were removing the wires, one of the wires got a crack and now leaks past and onto something else, that is why I said check at night. Always remember when you have problems, what is the LAST thing you did, my guess is either a wire cracked, a plug got cracked around the insulation or you mixed up 2 cylinders.