Changing Spark Plugs

The best way you can replace the spark plugs on the passenger side is you need to remove the air intake duck. Then you can stick your hand under neat to remove the spark plugs.
Tran

Hi i just changed my spark plugs and started my truck now its sputtering and when i press the gas the car his little power and when its idling the car shakes not badly but at times theres a big jerk from the engine

were you sure that the gap is set properly? make sure plug wires are on the proper plugs in specific firing order. secondly did you route wires the same way if you replaced the plug wires. also make sure that the spark plug wires are properly tight on all plugs

The plugs came pre gapped i replaced the plugs one by one so none of the wires could have gotten mixed up. should i replace the wires? and also i forgot to put one of the wires back on the first time i started the car back up when i felt it running rough and then i stopped the car and put it on and it ran a little better but still puttering. Also thank you for the help with my problem

im aware that they are pregaped. but i have had them before be closed right up and improper. carefully check the gaps and make sure they are proper again. i hope you having that spark plug wire off didnt cause the coil to fry or even worse the ignition module.

ok checked the spark plugs today they were put in too tight so the plugs had to be regapped once they were back in the truck ran a little better for a little while now im hoping its not the coil or ignition module like you stated by the way the car still sputters and if i hit the gas the "Service Engine Soon" light will flash for a bit then be steady again

I have a 99 ford explorer with a 4.0L OHV engine that needs the #3 spark plug changed every 2 months or The following symptom occurs every 2 months.

The following symptom occurs every couple months then goes way completely after the spark plug is changed. On start up the engine will have a noticeable miss then after about a minute it will clear up and run fine. When driving 40-50mph light acceleration or cruse the engine will start bucking( missing) seems to clear if down shifted or accelerated. I tried ignition parts coil,wires.

The compression is fine. Ford changed ignition parts and intake manifold gaskets 8yrs ago and70K miles. Like stated before a new plug always makes it run good for while. No fouling or abnormalities on plug. Any ideas??? Thanks, J

ok your PCM has 3 diff outputs to the 3 coils the coils share 2 plugs each. since only 1 plug is acting up that points to the plug wire for the suspect cylinder. does the plugs color on that cylinder match the other same coil plug?

I have already traced the plug wire. Ohmed it out to confirm and even swapped the physical wire from cyl 2 and three. Still made no difference.The plug in cylinder 3 looks the same as cyl.. One time I swapped plugs from cyl 2 to 3 and the problem went away for 2 months.
Thanks,
J

have you compared the spark strength/quality on that cylinder?

Yes, and the cylinder relative to other cylinder seems fine. I have heard there where issues with the cyl head cracks etc. I tried removing the plug and re-torquing it. That did not work.No signs of head gasket issues. Any ideas?

Thanks,
J

try a hotter heat range plug? i had plug problems with a tempo and cured it by going to hot plug.

Same car, same problem. Only difference - cracked ceramic insulator on the spark plug #3.

I have changed this spark plug at least 9 times since I've owned the vehicle. I torque the spark plug and ensure the gap is correct each time.
Explorer starting to act up again. I think I'll try the hotter plug idea. Will be repairing a valve cover leak soon, so I think I'll change the inject in that cylinder too. Can't hurt

I chased this problem for several years. You have a small crack in the head between the intake valve and exhaust valve. This is very common, perhaps inevitable on a 98T head. Coolant leaks into the cylinder when the car sits and it runs rough for 10 to 20 seconds after a cold start. After 2000 to 3000 miles the coolant contaminates the ceramic on the plug and it becomes electrically conductive and causes a misfire. You change the plug and you are good another 2000 to 3000 miles. This occurs on the #3 cylinder (back passenger side) and #4 cylinder (front driver side). K&W block sealer may plug the leak a bit and you can get more than 2000-3000 miles out of a plug. The only real fix is an aftermarket head that has more metal at the point where is cracks. That's what I did for mine. Google "Ford 4.0 ohv cylinder head crack" to see pictures. Good luck.