Does bad coil always=check engine light

[davito]

My cars mpg drop by 3-4 and it is starting to miss. I have searched. Some people reported cel for coils IIRC.Do they always throw a code? My car is a 01 v8 with 80k miles, would it be better to just change all the coils to save doing this again later?

Thanks for your help

 

[jumpman6235]

nope, not always throws a CEL, .... mine became a problem at about 75K, and no CEL until i brake torqued.. You should just replace all coils, spark plugs and valve cover gasket

 

[davito]

DID YOU DO YOUR OWN/ How long did it take. I have some mechanic ability.
Ford motor parts for everything?

 

[jumpman6235]

no i didnt do my own, i have a v6 and its harder to replace the coils compared to the v8... Yes, all Ford motorcraft parts is recommended.. Look in the Tech articles, you will see is DIY for the v8 coils

 

[lseguy]

Often the CEL light wont come on until you REALLY push the engine..ie the braketorque referenced above.

On a V8, it's a moderately difficult job, mainly on the drivers side due to all of the components in the way. But if you can change brakes, rotors, and other general maintenance, you should be able to do this. Give yourself several hours, plenty of light, and the right tools.

As far as Motorcraft parts, I disagree. AutoZone and/or AdvanceAuto used to carry the Visteon Coils for around $40 each..and if I am not mistaken, Visteon is a supplier of O.E Ford/Lincoln products.

If it were me, I probably would not waste money changing ALL of the coils. I'd give her some full throttle runs, and try to get that CEL light on first so you can tell which one(s). are actually bad.

 

[davito]

Thanks for the advice. I just feel odd about running it hard while it is missing, but I it would help if it would throw a code.

 

[FastNsmoothLS]

Not always

Mine had the same problem, 3 months, no code. Bad mileage, misfire and pulling. So I opened the covers, and boom... oil in the wells. Also had water marks. Only replace the three that looked the worst and that solved the mystery. I know I have one more bad on the same side and it's getting worst now, so I'll replace that one tomorrow, Saturday. It's easy, 02 V8.

 

[beaups]

did you lose engine power...kind of a chugging sound at low rpm's?

 

[FastNsmoothLS]

Yep

And also, when cruising, slowly give it gas without provoking an overdrive, and feel the pulling/misfire.

 

[beaups]

sorry for 20q's...was it smooth during light normal acceleration but seemed to rev a lot higher than it should and jerky shifts?

 

[FastNsmoothLS]

Not always

but It got worst by the day. It would get worst as the car warmed up during the day, frustrating when under full throttle. No power but lots of noise and pulling from the engine.

 

[FastNsmoothLS]

but It got worst by the day. It would get worst as the car warmed up during the day, frustrating when under full throttle. No power but lots of noise and pulling from the engine.

It would feel somewhat smooth until it reached the shifting point, then I could feel the jerking, like taps...

 

[TheRebel]

It would feel somewhat smooth until it reached the shifting point, then I could feel the jerking, like taps...

A little off subject, but when my car did this, I had a bad transmission solenoid.

 

[beaups]

but It got worst by the day. It would get worst as the car warmed up during the day, frustrating when under full throttle. No power but lots of noise and pulling from the engine.

what do you mean by "pulling"? can you try to describe the noise, too? thanks

 

[2001LS8Sport]

Often the CEL light wont come on until you REALLY push the engine..ie the braketorque referenced above.

On a V8, it's a moderately difficult job, mainly on the drivers side due to all of the components in the way. But if you can change brakes, rotors, and other general maintenance, you should be able to do this. Give yourself several hours, plenty of light, and the right tools.

As far as Motorcraft parts, I disagree. AutoZone and/or AdvanceAuto used to carry the Visteon Coils for around $40 each..and if I am not mistaken, Visteon is a supplier of O.E Ford/Lincoln products.

If it were me, I probably would not waste money changing ALL of the coils. I'd give her some full throttle runs, and try to get that CEL light on first so you can tell which one(s). are actually bad.

You don't have to have a CEL to have a code set. Have it scanned and see if there's a code in there. The parameters for setting a code and turning on the light are different. It will not pop the light for every little hiccup the car sees. Yet it will store the code in the ECM for a period of time. There are such things as hard codes, soft codes, etc. I would have it scanned to see if something is there.

 

[lseguy]

Ahh...I did not know that. Thanks for the knowledge, 2000Sport!

 

[davito]

thanks for the help! I will try to get it scanned today