Hesitation under hard acceleration

[mmaylock]

Recently I've started getting a hesitation while trying to pass or in any situation requiring hard acceleration. I can't tell if it's engine or drive train related. Has anyone experienced anything similar and do you know what might be causing it?

I'm considering taking it to the dealership but thought I'd check here first in hopes that it's something simple.

Thanks...

 

[Whack]

Recently I've started getting a hesitation while trying to pass or in any situation requiring hard acceleration. I can't tell if it's engine or drive train related. Has anyone experienced anything similar and do you know what might be causing it?

I'm considering taking it to the dealership but thought I'd check here first in hopes that it's something simple.

Thanks...

Year? Miles? Ever replace the plugs or Coils?

Whack

 

[GAINMOB]

check ur manifold for leaks...I had similar probs and both manifolds needed to be fixed

 

[mmaylock]

Year? Miles? Ever replace the plugs or Coils?

Whack

2007 - 120,000 miles. I replaced the plugs at 100,000 miles. Did not replace the coils.

 

[k9education]

2007 - 120,000 miles. I replaced the plugs at 100,000 miles. Did not replace the coils.

I guarantee that someone is planning on telling you that you must replace the coils, but they don't necessarily ever have to be replaced. Check them and if they look good, leave them alone.

 

[mmaylock]

I guarantee that someone is planning on telling you that you must replace the coils, but they don't necessarily ever have to be replaced. Check them and if they look good, leave them alone.

Will do. What am I looking for when inspecting them?

 

[Flexpedition]

Nothing to really check on a coil pack other than visually looking at it for external damage like it being cracked or melting, that its snugly in place, etc. If it was misfiring, even periodically there outta be a code present or pending. You didn't mention your check engine light being on, so we'll assume no code was thrown, but you could still use a code reader to see if anything is pending. What brand/model plugs did you install 20K ago? Did you check the gap on them? Air filter clean and changed regularly, using a stock housing? Can you see a dark ring of gunk around the throttle body plate? Have you ever cleaned the mass air flow sensor? Has transmission fluid ever been changed?

 

[GAINMOB]

I guarantee that someone is planning on telling you that you must replace the coils, but they don't necessarily ever have to be replaced. Check them and if they look good, leave them alone.

they are supposed to be replaced at 100K...so if u haven't done the 100K maintenance I would start there as it calls for plug and coils to be replaced along with other stuff

 

[JollyRoger]

Nothing to really check on a coil pack other than visually looking at it for external damage like it being cracked or melting, that its snugly in place, etc. If it was misfiring, even periodically there outta be a code present or pending. You didn't mention your check engine light being on, so we'll assume no code was thrown, but you could still use a code reader to see if anything is pending. What brand/model plugs did you install 20K ago? Did you check the gap on them? Air filter clean and changed regularly, using a stock housing? Can you see a dark ring of gunk around the throttle body plate? Have you ever cleaned the mass air flow sensor? Has transmission fluid ever been changed?

X2 on the above. Been down this road with both an '07 and '10. My list of things for hesitation/misfiring are:
Air Filter
Clean Mass Airflow Sensor
Clean throttlebody
Replace Spark Plugs
Replace COPs-no, you can't tell if they are bad by looking at them or metering them.

Those four things will typically result in noticeable improvement.

Somewhat related: I just replaced the VTC Solenoids on my '10 to take care of a wicked 'diesel-like' condition that happened occasionally when idling. The old ones were visibly bad. After replacement it not only eliminated this problem, but remarkably improved throttle response because it now instantly puts the valve timing where it needs to be when taking off from a stoplight. I can really tell the difference, and honestly didn't know the engine could run 'this good'. Really glad I did that, although it was a serious PITA!

Good luck!

 

[k9education]

I guarantee that someone is planning on telling you that you must replace the coils, but they don't necessarily ever have to be replaced. Check them and if they look good, leave them alone.

they are supposed to be replaced at 100K...so if u haven't done the 100K maintenance I would start there as it calls for plug and coils to be replaced along with other stuff

According to who? The COPs are not listed as a scheduled maintenance item in the owner's manual or the service manual for that matter. I know they're a common problem on some model year Expeditions, but if they're not throwing a code, showing any signs of damage (e.g. cracking), In the absence of a code or any visible sign of damage, I would leave them alone. If you're really convinced that one or more COPs is a problem though, test them (yes, they can be tested); don't just go replacing them for the heck of it. That's essentially what the stealerships do; just keep replacing stuff until the problem is resolved by dumb luck.

 

[Grgch95]

My 06 f150 5.4 is doing same thing when cold - below 20. Runs and goes fine except under hard acceleration. Supposed to be below 20 this next week here in so. IL Will see if I can get some codes and do some trouble shooting. I suspect mass air flow sensor and will start there. Will post results.

 

[JollyRoger]

According to who? The COPs are not listed as a scheduled maintenance item in the owner's manual or the service manual for that matter. I know they're a common problem on some model year Expeditions, but if they're not throwing a code, showing any signs of damage (e.g. cracking), In the absence of a code or any visible sign of damage, I would leave them alone. If you're really convinced that one or more COPs is a problem though, test them (yes, they can be tested); don't just go replacing them for the heck of it. That's essentially what the stealerships do; just keep replacing stuff until the problem is resolved by dumb luck.

COP's get weak over time and can cause issues without throwing codes, nor looking cracked or damaged. I have found that tests are inaccurate. I've metered known bad COP's which have shown the exact same ohms as a brand new one. Using a spark tester only indicates spark/no spark. A typical symptom I've found on bad COPs is that they randomly deliver less voltage than they are supposed to, and a spark tester won't show you that. I'm sure that the dealer has some way to know exactly how they are performing, but I don't have access to that equipment nor do I want to invest that much in test gear. It's easier for me to just put a new set of COPs in and be done with it.

I've replaced them on two different vehicles, and both times this effort has cured the problem. Neither vehicle had generated any codes, nor were there any visible deterioration. Just my 2 cents...

 

[mmaylock]

Nothing to really check on a coil pack other than visually looking at it for external damage like it being cracked or melting, that its snugly in place, etc. If it was misfiring, even periodically there outta be a code present or pending. You didn't mention your check engine light being on, so we'll assume no code was thrown, but you could still use a code reader to see if anything is pending. What brand/model plugs did you install 20K ago? Did you check the gap on them? Air filter clean and changed regularly, using a stock housing? Can you see a dark ring of gunk around the throttle body plate? Have you ever cleaned the mass air flow sensor? Has transmission fluid ever been changed?

UPDATE: I took it to the dealership, and of course, I couldn't get it to happen. The service manager (good guy btw) hooked up a laptop to the ECU and had me take him for a drive. I jumped on it and couldn't get it to happen. He told me that it could be the transmission. He said there was some type of valve (i forgot the specifics) in the transmission that may be getting stuck. I had the trans filter/fluid replaced a little over a year ago. He also told to keep track of the conditions each time it occurs.

Has anyone else experienced anything similar that turned out to be something wrong with the transmission?

 

[sentry6]

Guaranteed its the coil packs. I have had to replace them several times on my explorers with the 4.6 and my 5.4 expedition. the link below, these coils have been great. solid copper and have had no issues. and only 40.00
Amazon.com: ENA® Lifetime Warranty New Set of 8 Straight Boot Ignition Coils for Ford Lincoln Mercury V8 V10 4.6l 5.4l 6.8l Compatible with DG511 C1541 FD508: Automotive

 

[mmaylock]

PROBLEM SOLVED:
After successfully demonstrating the problem to the dealership drive-ability tech while he had his laptop hooked up to the ECM, it was clearly a misfire problem coming from cylinders 5&6 with some intermittent misfiring from #8. The dealership quoted me $474 to replace all 8 Coil pack boots and plugs. (The plugs were already replaced 20,000 miles ago). After pricing out the boots ($6.00 ea.) and checking the difficulty of replacing them myself, I decided to do it myself. But before replacing them, as a quick experiment, I took out the existing #5 boot and applied dielectric grease to both ends of the spring. Bingo! No more misfires. It was easy enough that I did all the springs on #'s 5-8.

Net-net, for $1.97 and about 20 minutes, I fixed the problem. It has more power and seems to shift better than it has in quite some time.

My advice to those of you who think you MAY have a coil pack problem, try the dielectric grease on the springs first. It's a cheap experiment and may solve your problem...

 

[GAINMOB]

That is EXCELLENT!!!

Mr. 10K