Hey all,
I wanted to get your thoughts on this somewhat annoying issues I'm having. Basically as the title suggests, I am seeing some stuttering (almost sounds like very mild missing or vibration during acceleration) in higher gears 8-10 (RPM 1900-2100) when under some heavy load. I came across this first while under cruise control at 80 mph around some hilly terrain. I can cruise at 80 and when I would get to a mild to medium hill in 9th or 10th gear,, the RPMs and boost would slowly climb and start to vibrate or stutter a bit starting around 13ish psi up to 18-19 psi. If the hill was too big the truck would down shift and there would be no problem. I can replicate this feeling by putting the truck in M9 and getting to higher load. If going on a perfectly flat road or slightly down hill, I don't really feel it. During this my tuner doesn't show any misfire or abnormal knock or anything obvious.
Now for the truck details. Its 17 with 54K miles. Plugs were changed 2k miles back with SP578 plugs. The truck is tuned (engine and trans) and when I flash to the stock tune, I am 95% sure the problem doesn't exist or is so subtle it's unnoticeable. However, I haven't driven it a ton on the stock tune so I'm putting 95% sure. Also may be worth mentioning, I am on 37s (Yokohama MTs).
Any ideas? I am thinking of swapping to colder plugs (Ford Performance SP542 replacements). But I also read about 03'Darin's issues with something that sounds similar in the past that sounds that boiled down to rapid PCM adjustments to the throttle position under high load even with constant pedal input.
Now I may just try some of those plugs since its a cheap try and don't really lose anything. I don't necessarily want to mention the tune company as I don't want this in anyway lead to feedback towards them. But it is a well known tune on here. I am working with them as it's custom to the truck.
I wanted to get your thoughts on this somewhat annoying issues I'm having. Basically as the title suggests, I am seeing some stuttering (almost sounds like very mild missing or vibration during acceleration) in higher gears 8-10 (RPM 1900-2100) when under some heavy load. I came across this first while under cruise control at 80 mph around some hilly terrain. I can cruise at 80 and when I would get to a mild to medium hill in 9th or 10th gear,, the RPMs and boost would slowly climb and start to vibrate or stutter a bit starting around 13ish psi up to 18-19 psi. If the hill was too big the truck would down shift and there would be no problem. I can replicate this feeling by putting the truck in M9 and getting to higher load. If going on a perfectly flat road or slightly down hill, I don't really feel it. During this my tuner doesn't show any misfire or abnormal knock or anything obvious.
Now for the truck details. Its 17 with 54K miles. Plugs were changed 2k miles back with SP578 plugs. The truck is tuned (engine and trans) and when I flash to the stock tune, I am 95% sure the problem doesn't exist or is so subtle it's unnoticeable. However, I haven't driven it a ton on the stock tune so I'm putting 95% sure. Also may be worth mentioning, I am on 37s (Yokohama MTs).
Any ideas? I am thinking of swapping to colder plugs (Ford Performance SP542 replacements). But I also read about 03'Darin's issues with something that sounds similar in the past that sounds that boiled down to rapid PCM adjustments to the throttle position under high load even with constant pedal input.
Now I may just try some of those plugs since its a cheap try and don't really lose anything. I don't necessarily want to mention the tune company as I don't want this in anyway lead to feedback towards them. But it is a well known tune on here. I am working with them as it's custom to the truck.
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