i have a 04 f150 with a 5.4 3v engine. i am experiencing hesitation at high rpms around 3000 rpms. i can hear it missing. this has happened after i installed roush dual exhaust. i can hear and feel this. i took to ford and they said nothing is wrong and everything is normal. bull ****!!! it didnt do this before the exhaust install. anyone have any suggestions??? thanks

 

An exhaust will not cause those symptoms. That is ridiculous.

 

well it didnt do this on the way up to the exhaust shop so....???? obviously it did. some people are saying u need to get a tuner??? i dont see why u would need a tuner for exhaust?

 

Once again, a cat back exhaust will not cause an engine miss, no matter how much you think otherwise.

You don't need a tuner for a cat back exhaust like the Roush.

You already have stated in another thread your truck has had engine problems in the past that have been repaired under warranty. I'd start with that before I'd blame an exhaust system on a miss.

 

well i did start with that. i took to a ford dealer and they are saying nothing is wrong. as weird as it sounds, thats whats happening. my truck has never done this before the exhaust install. so how could this not be from the exhaust?? im not trying to sound like a dic but i know what the truck is doin and how it sounds. like i said earlier, this is very weird. if i was readieng this i would say that its bull **** as well. but thats whats happening. any clue on what may be causing this if i still had the stock exhaust on?

 

How could it be from the exhaust?

 

i have no clue thats why im asking. trust me this is crazy. when i mash the gas pedal its hesitating around 3000-4500 rpms. i guess ill just put the stock exhaust back on(which i no longer have) im just looking for an answer or some advice

 

There has to be something else causing the problem you're having. The only way an exhaust will cause hesitation is if your cats are stopped up, which has nothing to do with your new cat back.

 

ok thanks for the input. ill continue to research or probably just put my stock exhaust on and see what happens. thanks again i appreciate it

 

Your not going to be happy when you find out that by putting the stock exhaust back on that your problem will still be there.
Just so I understand this right. You purchased the Roush dual exhaust system which connects to the original Ford exhaust pipe after the "Y", correct. If this is the case, then remove the roush system and take it for a drive with an open pipe. Not going to hurt anything but you might tick a cop off.
I'm betting that you will still have that "Miss" and hesitation.
You need to remove what you think might be the problem before you go throwing good parts away. I'm guessing you can have that Roush system out in about a 1/2 hour. I bet your going to say, well I need back pressure from a muffler to have the engine run right. I ran a straight pipe in place of the muffler for as long as I could. I bought the truck used that way and had no running issues. Only reason I put a Flowmaster on is because the straight pipe rusted through at the clamp connection and I got sick of the police hitting their break lights to let me know that I was pushing the law a wee bit.
That and my wife would ride in the truck again. My 12 yr old son thought it was whimpy.

 

correct, that is how its installed. ill try doing what u said. trust me i love the exhaust and i dont wanna have to put stock back on. illl try this today. thanks!!

 

I remember Jbrew joking with someone one time about checking for a "potatoe" in the exhaust. Reason, I bring this up is, make sure when you tear down the Roush system that the installers didn't leave anything in the system or mechanically do something that has seriously restricted the flow of the exhaust.
Just a thought and something to check for.

Other than that, enjoy the ride with an open exhaust, your going to turn some heads for sure.
I ran mine open for a couple of days just for fun. I ran it open from where I am guessing they connected your Roush system.

TJK

 

I know you said you took it to ford but could it still be the injectors? My 05 did about the same thing one of the times I had injector problems.

 

ok.... so i just took my truck back to the dealer this morning to have a tech ride in it with me. reminder: they looked at it and drove it around yesterday and said nothing was wrong and they didnt hear or feel a miss. so me and the tech took a ride and the problem happened right away. he said yes, its definitely has a "miss". he said a 95% chance that a plug is messed up and recommeneded all new plugs. its pretty expensive. i then asked why it only started doin this after the exhaust install and he stated; that ive changed the amount of air flow.... is this bull **** guys or what?? i just dont wanna pay to get them replaced and have the same problem...??

not sure about the injectors mustang cj. they siad it was fine???


thanks guys

 

Is he referring to the exhaust airflow. If he is, sorry, I don't buy it.
By the way, I see you have a 5.4L, but how many miles on it and have the plugs ever been changed. Wish you knew a good mechanic with a SnapOn Modis Unit. He could tell you alot about your engine performance. I am lucky, I have a friend who owns a garage and owns a Modis unit with all the software packages available and upgrades.
I am not disagreeing with the Ford Tech, but just driving it and saying you need new plugs without throwing it on a Ford OBD system Scantool is not sound advice to me.