Will the computer generate or can you pull codes if you are having a problem but no "check engine" light??

Truck is running like crap. Has a bad hesitation all the time as if it's running on 7 cyl's..except not quite that bad. I can drive it if I have to. Funny thing is, it started but is progressively getting worse. Nothing obvious wrong so I'm lost...but, no check engine light. Figure I'll take it to a dealer and let them tell me what's wrong then bring it home and fix it.

 

Its possible, but for something as bad as you are describing you would usually get a CEL for that. But its worth going to AutoZone and having them scan it before going to the dealership.

 

Just last week I had a similar problem that began in April when I took a Sturgeon fishing trip to the Columbia River in Portland, OR. Going, I noticed only a slight variation in the cruise control even engine sound, coming back I only noticed this again a time or two. A month ago, I began to worder if my fuel filter was bad. So, I had it changed at the time of my oil change. Last week, the engine was missing like crazy and driving me nuts. Finally my 'Check Engine' light came on. The dealership told me it was my #5 coil pack and that they could fix it the next day. $231. later it was fixed and now runs as good as it did the day I got it.

So, my money would be a coil pack problem. Hope this helps you out.

Mert Leeper

 

Ya know, I thought about that but then I was wondering...do they progressively go bad or do they just "go"?? I had one go bad before (ironically the #5 coil...I **** you not) and it just went ka-put, nothig progressive about it. Can that happen? That would still lead me to my original question...will it give me a code with no check engine light on?

That sucks cause mine went bad on vacation on the road. No tools or anything. I was at the stealerships mercy and paid about the same thing you did. I later found factory replacement coils at www.rockauto.com for around $50!!! That's what I'll do this time for sure.

Here's another question about coils...Do they perform at different levels? Like can you have some running great and some running just OK?? Would replacing all of them add any performance value? Can't imagine it would at only 55,000 miles though???

 

Galaxy

A coil pack is nothing more than an electrical component. It can go bad at 55K miles or 155K miles. My experience is they go quickly enough you will receive a misfire. Now does that mean it lost complete conductivity, or is faulty enough to reduce the voltage required to cause a misfire?

Have your system checked. I would suspect if it is running as bad as you say it is there may be a code there.

In my 2000 5.4L Lariat I have had problems with #7.

 

Several of my friends in the Denver area drive F-150's and the overall opinion is they can go bad all at once or like now! My close friend drives a 1997 F-150 Extended Cab Lariat - he has 108,000 miles and changed a coil pack at 99,000 miles. The problem cropped up over about a three month period, just like mine, and then finally the check engine light came on. Until this happens, I don't think you can tell which coil pack it is, unless you have a zillion dollars worth of computer dino equipment. The stealership can make that determination. Or one of the auto parts stores can tell you when the 'check engine light' comes on and they can code it.

I would not change all of the coil packs, they are either working at peak or are not. Just change the coil pack in which the problem occurs. Also, the stealership replaced the spark plug at the same time.

Hope our collective comments help you. Mert

 

Yes, you can have codes and no check engine light. In fact, yesterday my engine felt like it was "stumbling" under load so I hooked up my scanner even though the check engine light was not on. Sure enough it came up P0304, probably the most infamous cylinder to go on the 5.4 because of a coolant leak near the rear passenger firewall. I had to replace that COP at 100K and now I went another 40K before it went out. I couldn't tell any signs of leakage but I guess I'll try to tighten up that clamp back there on the coolant hose before I replace the COP for a second time.

 

I remember going threw the coil over plug drama , #4 even had rust on the top of it lol, I started out replcing two COP's and still had that studder -shudder after hitting overdrive . I ended up buying the COP kit on ebay that came with motorcraft plugs for a little over a hundred dollars, best investment I ever made. Look up Global Automotive on ebay or just punch COILS in and you'll find them.
Coils can pass primary and secondary testing and still be bad under a load. The only way to test for a bad one is a mode 6 scan or something that will read cylinder history. Lookup misfire in forums ..Good Luck

 

Hey, just remembered something...I have a coil (#2) with the little ear broken off. It's broken off just the part where the screw goes to hold it in place. Nothing else was wrong with the coil. It's been like this for a few thousand miles. Anyways, I remembered I had this so I decided to swap coils around and see what happened. I swapped #1 and #2. Cranked it up and it ran exactly the same BUT, the check engine light was immediately on. I switched them back to the original locations and the light went out!! Mean anything. I'm gonna borrow a known good coil from a buddy and throw it on that #2 and see what happens.

 

The only other thing it might be is your ports are clogged (upper intake) - you might wanna pull your thottle body or clean the inside with a good set of p1pecleaners - clean everthing , even your IAC spring mech. then WD40 and 60lbs of compressed air only - blow it out .. Clean your MAF , be super careful. A littlle achohal and a very soft brush and only 30lbs of compressed air. Reset your comp- disconnect batt. 4 1 hour. re-connect, start , gradually accell to 60mph let off , do not touch your brakes or the accelerater until your vehicle decels to 40mph under it own power. Do this three times within the same drivecycle. The second time zapps your pram. The third time tunes your vehicles air fuel ratio the best possible settings. Remember this has to done within the same drivecycle (don't turn it off until complete or it will be compromized) This can be achieved anytime within the cycle. Good Luck!!

 

Are you messing with me to get me to go out and drive like that Just kidding. I'll give it a shot for sure. Anyways, tonight I snagged a coil off my buddies truck and threw it on that broken #6 spot...that ain't it. Didn't change a thing. BTW, just out of curiosity, where did you get that procedure?? First time I've ever heard of that.

 

LOL - That's funny .. Nope I'm seriouse about that procedure. I had a bad COP and it misfired under a load . I would go through the procedeure every three days or so until my new COP's arrived , the truck would run half way decent for about 300 miles and then very bad due to my COP's being faulty. I 'll tell you right now, I 've done 3 5.4L's with these COPS from Global Auto and the difference is like night and day. I've posted many procedures over time and dramas that I went thru when I first started working on modular motors - Trust me , COP's just don't stop working..With the High tech 5.4 motor it's more of a integrity thing and it's picky. If your running any plugs other than Iradiums, Motorcrafts or NGK's then your truck is not running correctly - look at the plugs..A busted ear does not effect proformence or act as a ground, but if you don't use di-electric inside the boots then your loosing power - Lots!! If your boots are dry look inside and you'll see arce scores down the inside of your boots, if you don't use di-electric grease between the outerboot and cylinder head then it won't be long befor there compromised once again..Some things to remember that make a difference..

 

Found it. How on gods green earth do they sell that kit for that price?? Rockauto.com has those coils for $53 a piece, which is a great price. That's amazing. I just reconnected my battery and getting ready to head to autozone and borrow thier code reader. I checked the MAF and everything else I can think of. I've found nothing obvious.

 

Well, the little disconnect the battery/driving technique didn't do anything...but it did make the check engine light come on. Which had not been on until now. Wasn't able to get a code reader so I'll have to go back later.

 

OBD1 trucks for sure don't always flash a code when present. I thought the OBD2 trucks did always flash, but I guess not.

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