Spark plugs and Spark plug wires?

Question

My husband changed spark plugs and spark plug wires in my ford explorer yesterday. Now it isn't running correctly. Almost like the engine is shaking. Anyone know if you can buy bad spark plugs or spark plug wires?? Any ideas what may be wrong?

Thank you everyone. Especially Bobweb and John Paul!! We took your advice. While husband was checking everything he discovered one of the new spark plugs was cracked. I appreciate your help very much!

Answer 1

That's definitely a symptom of an ignition misfire that could be caused by spark not getting to your spark plugs properly. Once you've rechecked the part numbers that were installed to make positively sure they're the right ones for your vehicle, then recheck the firing order and that the right plug wire goes to each spark plug. Make sure each plug wire connector snaps on well to each end of the plug wire. Make sure the plug wires are routed in the original way across the engine so that you don't get the wires hitting hot engine parts and having the spark jump over to ground. You can raise the hood on a real dark night and see if any sparks are jumping to ground as someone punches the accelerator pedal. Sometimes the coil pack tower contacts get build-ups of oxidation (white stuff on the aluminum contacts) that has to be cleaned with a small wire brush inserted down into the contact.

Answer 2

It is possible to get bad wire or bad spark plugs or the wrong spark plugs. It is not that common through, it is more common to get the wrong spark plugs or mix up the spark plug wires. But you can not miss wire just one spark plug wire, and with the coil packs per cylinder one would really have to work to miss wire it. So I am assuming that you have a Ford Explorer with a rotary distributor, and either a 6 or 8 cylinder engine.

Tell your husband the problem and have him recheck his work. Get out your owners manual and make sure you have the right spark plug for your vehicle. Verify that the spark plugs are proper and securely fitted, that the spark plug wires are securely fitted, and that the wires are wired to the right plug. depending on what year of ford you have this should be very easy to do but you will have to know the firing order.
Get a repair manual from the library or look it up via the Internet normally the firing order will have a diagram that show how the spark plug wire run.
If all seems in order or this is beyond our ability then visit a reputable garage or ford
dealership. You do not want to drive if avoidable, you may cause more severe damage.

Best of Luck

Answer 3

More than likely, the wires were not put in correctly. The wires must be put in according to firing order. This means that a wire goes from one particular spot on the distributor cap to a specific spark plug (cylinder). Find out the firing order (probably by purchasing a repair manual) and check for correctness. Another possibility is that the spark plugs are not correctly gapped. This can be checked by finding out the proper gap (consult repair manual) and buying an inexpensive gap mesaurer to measure the gap (available at any auto parts store). If incorrect, purchase a gapper, take out all spark plugs, and adjust to proper gap (this is a simple procedure). After these basic steps have been checked, if you are still experiencing problems, than the wires or plugs are probably defective and should be replaced.

Answer 4

It is easy to break the white portion of the spark plug it is also easy to cross a couple spark plug wires. Don't drive until repaired because misfire can overheat and dammage expensive cat converters. Flashing check engine light means dammage is being done. Light on steady P0300 random misfire and P0301 thru P0308 are cyl's #1 thru #8 unless yours is a V-6 engine. Auto zone can tell you where to look if the light comes on. If not there might be something that was removed moved or not reinstalled correctly causing a vacuum leak. Vacuum leaks cause a lean P0171 code and random misfire most times. Cars these days only need tune -ups when there is a problem or engine light many have spark plugs good for 90 or 100 thousand miles

Answer 5

Could be a bad wire or spark plug, but my guess is the wires were connect in the wrong sequence.

Answer 6

Could be that he may have the firing order wrong.Might also be a loose or improperly seated plug wire,mis-gapped plugs,or indeed a bad plug.Check the firing order first and then continue in order to find the problem.Also,did he replace the distributor cap?A very slight hairline crack could easily cause the same problem....Good Luck

Answer 7

each plug has to be plugged into the correct firing order in order to run smoothly
for example a firing order might be 13578642 if spark plug 3 is plugged into 5 spot the car will run rough

Answer 8

if you pulled multiple plugs at the same time, then you could have a misfire from wires that are not routed to the right plug.

Answer 9

Have him recheck the plug wire connections first, then if all are snapped on good, recheck the plug wire placement by firing order. I bet he has two of them out of sequence.

Answer 10

try tightening up the spark plugs, they could be loose.