98 F-150 4.6 auto, on acceleration engine is clattering very bad. it runs fine but clatters as you gain speed or throttle up. acts like it is retarding the firing way to much. have had this problem for years and can't narrow it down. there have never been any weird codes or anything like that. truck runs and performs fine it just has always had this issue. this is my dads truck. he thinks the firing is getting retarted way to much, maybe something with the knock sensor, but parameters all check out. to me it sounds like something to do with the exhaust system. does not do it at idle only when under a load.

 

Sounds like possibly a detonation problem. You might try cleaning the MAF.

 

I hate to address this way but what are specifically refering to as clatter?
How does the truck run fine with a problem.
Maybe it isn't the engine making the noises you hear.
Timing retard would make the engine very sluggish but your not indicating this.

 

thanks lxman1

i will look into the maf

do you think it could be the knock sensor. can you explain how the engine uses the maf as far as detonation goes. i thought the maf was used to determine volume of air flow and air temp. thanks for the help.

 

could this be the infamous exhaust manifold studs rusting issue?

 

I just changed my plugs and the engine is running real smooth. However, I'm experiencing a problem like this too. I don't know if it is the exact problem listed. But the truck seems to have good acceleration, but there is a weird shutter or vibration. It seemed like a wheel way out of balance. I did not have this before the spark plug change. But I'm not getting a code either. There were a couple of accelerations when I heard a pop or a sputter. But again, no check engine light and no code. I know it is suspect because of the plug change that it is connected but all my wires are seated well and plugs gapped correctly. Prior to changing my plugs, I had a check engine which is now gone.

 

thanks guys. my dad is getting on in years so i am trying to help him on this. that is what i thought it was, some sort of exhaust leak, since the engine is making this sound but with no significant loss of power or fuel mileage. can you tell me what side is usually the guilty one. thanks for the help.

 

i THINK the passenger side...but the other guys on here can tell you better

Here's the TSB https://www.ford-trucks.com/tsb/full...php?tsb=05-5-4

 

You might want to check to see if there is something banging arround in the exhaust system. I had similar problem. Ford told me that I needed a new motor. Turns out part of the passenger side cat had come appart and was bouncing arround in side one of the pipes. The sound got progressively louder as the months wore on until one day I stopped driving beacause it got so bad. No power loss or anything to contribute to the motor itself. One day i got underneath the truck and banged arround on the exhaust and heard something bouncing arround inside. It was a piece of ceramic material that had broken off. Also check to see that the flywheel is bolted down tight. Good luck !

 

i believe there's a TSB on this site for that too....
off to PepBoys for the BOGO free of Techron...