My truck is having some issues as I accelerate. Sometimes it does it, and sometimes it won't. As I accelerate, it begins to shake as if there is not enough power to boost it. It happens more frequently between 45 to 60MPH, yet once it goes past 60, its fine. Today it started as I accelerated from 0. NO ENGINE LIGHT HAS COME ON!! Thats the weird part, so it has been really hard to diagnose. Ive already cleaned the MAF sensor, throttle body, and even replaced the Idle control Valve. No luck!! Any ideas what might be going on? HELP!!

 

That sounds like a bad COP causing a misfire for sure... Mine was the same and no codes. Well, no CEL but there was a code. Hook it up to a reader and see if there is any stored codes to let you know what cylinder. How old are your plugs?

 

Jspansel...
My plugs are about 6 months old. I'm hoping one the COP's is the issue. Can't think of anything else anymore. My PCV valve connector was bad as well had both replaced, but no luck. Still no service engine soon light coming on. Thanks for your input. Will keep you posted.

 

What brand plugs did you use?

 

I used Motocraft.

 

I got on a roll here, so apologies for the long winded post:

GVera04, go to any AutoZone and they will put a code reader on your truck for free and tell you which cylinder is the one that is misfiring.

I've had the same problem several times and it was always one of the COP's, I have replaced three (#'s 7, 6 and 3, in that order) since I've had the truck (About 8 months), I have also replaced 4 on my 2001 Mustang. Luckily they both use the same COP's and I had a spare from my Mustang when the first one on my truck went bad.

Two of the three times I didn't get any light or a code, until I went up a hill right near my house and like you said, it really bucked and stuttered from about 40-60mph with light to medium throttle, after about two or three trips up that hill, then the light finally did come on.

Funny though, when it started bucking like that I'd get frustrated and if I floored it, it accelerated like normal.

The last time when I removed the COP, I removed the boot and spring from the actual coil top and there was quite a bit of moisture in the boot. I dried it out and reinstalled it and it worked fine, but I took it back off and replaced it anyway, just in case.

When replacing the COP's remember to remove the boot from the COP and use dielectric grease where the boot and coil come together, also around the top of the boot where it seals against the valve cover and most importantly in the end of the boot where it contacts the spark plug.

The grease is an insulator hence the term dielectric, so try not to get any of the grease in the spring where it will connect to the plug and cause the very misfire you are trying to correct.

The grease also serves another function as it lubricates the boot making it easier to get fully seated on the spark plug, and makes it easier to remove when it comes time to replace them again.

That time will be much, much later by following the above suggestions than if you do not use the grease in all three locations on the boot.

If you did not use the dielectric grease when the spark plugs were replaced, this may be somewhat self-inflicted.

Good Luck!

 

BlackFerret, thanks for the good input. I will definitely follow your advice. One question, when you took it to Autozone, was your check engine light already on to detect the bad cylinder??

 

I had the same symptoms after I washed my engine and the CEL would not always be on. At first I noticed the same misfire/rough engine stuff and later the CEL finally came on. I thought I fixed it by first cleaning up #8COP, CEL stayed off, but still some misfiring, esp around 40-50 mph, but eventually the CEL did come on again. I think you will find the problem cylinder if you hook up the code reader, even without a CEL present. I changed all the plugs, rebuilt the COPs with new boots and springs from o'reilly's and filled the entire boot/spring assembly with dielectric grease. The plugs had been previously changed by ford mechanics and had no grease at all on them.

 

Yes, the check engine light (Sometimes referred to MIL which stands for Malfunction Indicator Lamp. That refers to the Check Engine Light or Service Engine Soon light) has to be on for the code reader to output a DTC code.

There are some readers that will tell you that there is a pending code, meaning that there is something that might throw a code but hasn't yet, I have one like that, but AutoZone's usually don't have that type. After four COP's on my Mustang and three on my truck I finally decided to buy my own code reader.

The DTC codes for the cylinder misfires (Usual cause is a COP, but may be also be a spark plug):

P0300 Random/Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected

Keep us updated!

 

mcmarcia, good info but as I said above, by definition dielectric grease is an insulator and should not be put on the spring that connects to the spark plug, this may work in the short term but may actually lead to a misfire condition.

This is what is referred to as too much of a good thing is not good.

 

ooops, if I get any more issues, I will go in again and remember to clean up some of the grease. I figured it would help to displace water from the COP, no way I'm messing with it now with everything running good for now. thanks for the tip.

 

BlackFerret / Mcmarcia thanks for your input. Just hope this darn code comes up. Will keep you posted. Greetings from Brownsville, TX!! The southernmost part of Texas!!

 

When my C.O.P went, I just took each out. Before too long, you'll see which is f'd. Mine have been an orangey color and the ends ballooned. Sounds like the on set of a bad C.O.P to me, which I've never got a code for as bad aa it ran.

 

I've changed out 4 boots & spring, got a bit better. But still jerking at 55-60 now. Got the back two on each side to go.

 

PROBLEM SOLVED!!! Replaced boots & springs. Spark plugs were good, just cleaned them. One spark plug was full of gunk including the spring. Thank you for all your posts with suggestions!!