ive got a vibration at idle that smooths out as i accelerate...sometimes its worse than others and sometimes the check engine light is on all the time...randomly it will go off for a while and then come back on several days later...twice now i have been stopped at a red light and the vibration will get real bad, the light turns green i press the gas and get a verrrrrry slow increase in speed and rpm...ill have the pedal halfway to the floor and still nothing while the check engine light is blinking...after several seconds it will kick in and drive away fine...the truck is an 04 edge 3.0 with 89k miles

out of preventative nature and trying to figure out the problem ive changed the plugs, plug wires, and fuel filter (air filter, oil, and oil filter were also changed while i was at it...also had an alternator crap out on me.) ive also used the fuel injector cleaner you put in the gas tank and checked for vacuum leaks and cleaned the IAC...code reader pulls up cylinder 4 misfire and misfire under 1000 rpms....i suspect possibly the coilpack...is there a way to test it to see if it is working properly? all 6 plugs are firing

any other ideas of what it could be other than a bad injector?

 

you can test the resistances of the different circuits in the coil pack, not sure how on a 3.0.. should tell you how in a Haynes manual or at autozone.

 

Yea as mentioned there is a resistance range that the primary and secondary coil should be at. You can try that but honestly I would bet money they test fine. I have done a couple of vehicles now with similar nagging issues like you have described where the coil tests fine but replacing it fixed all of the problems. That's the issue with intermittent issues, if they don't do it all the time they can be a real pain to diagnose.

 

Ok...put in a new coil pack and it didn't fix the problem...any more ideas?

 

I had a similar situation on a 2.3L, turned out to be an intermittent Ignition Control Module... Most parts places can test both the Coils and ICMs... When they check the ICM, make sure they do it numerous times so the module gets to operating temperature...

 

I just had an issue on an 2000 Ranger w/3.0. Check the injector in #4. The way you are describing the issue it sounds almost the same as mine. I would start there.

 

The check engine light is flashing because the vehicle is in danger of causing permanent damage to the catalytic converter (expensive repair)..... Most often caused by a misfire or some other condition that will allow the vehicle to dump raw fuel directly into the exhaust, thus superheating the cat to a point where it will glow red hot and eventually melt the internals - not good. Since you have already replaced the plugs and wires, and the coil, and are still having the issue, you should look into fuel delivery. Try a fuel pressure test at "key on, engine off" and see if it loses pressure. An 04 with a 3.0 (i think i saw this description of your truck somewhere) should hold 60-65 psi. If your vehicle loses fuel pressure it may indicate a sticky injector. Most vehicles that are dumping fuel will blow a smelly thick white smoke out the exhaust. Since you had a cylinder 4 specific misfire, try swapping that injector with an injector from another cylinder. (this may not be a pleasant experience, but doing this stuff yourself can save you hundreds at a driveability diagnostician's shop) If the misfire moves to another cylinder, you may have discovered your problem. If that doesn't help, or if the problem is much more intermittent, you should suspect a deeper electrical issue. I hope this helps in some way. Good luck!

 

ok so it has gotten worse and now have a misfire in cylinder 4 and 6...both have low compression as well...a local mechanic believes it to be valve springs...any thoughts?

 

take an ohmmeter to the terminals of the coil pack and try to find the negative side and positive side of each coil pack.

 

put your tongue to it

 

ROFLMFAO! Yep... just like a 9V battery...

 

My understanding is coil packs fail in pairs. Think of the plug connections as 3 pairs. 2 x 3. If one fails the one next to it will fail also.

I had a dripping fuel injector that caused problems at idle. Its ruffly $120 to have all the injectors cleaned professionally.

I've also had a clogged cat. It was a whirring sound and the engine would max out to maybe 40 mph and no more.

 

ive already changed the coil pack with no improvement...im thinking valve springs now...ive got misfires in cylinder 4 and 6 now and both have low compression...i read somewhere that the valve springs are a common thing with this engine

 

What are the codes you are pulling with the reader?

 

I don't know if you solved the problem or not, but I had exactly what you are describing, ironically around the same milage. I did all the things you have tried. In the end it ended up being a cracked head. (covered under used car warranty for me), but once that was fixed I haven't had a problem (126k+ now).

Just throwing it out there.