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miq228 07-20-2007 04:25 AM

need help.. having problems after new muffler and intake..
im having some problems after new muffler(flowmaster 70) and intake kit(k&n air charger) installed

i installed muffler first then intake few days later

with new muffler, when i stop rpm goes down to about 900 then goes up to about 1100 then goes down to idle

im not sure if its normal or not, but i dont think my WK did this before

when rpm jumps, i could hear that new rumble

i just assume that it will go away after few days once car get used to new muffler

well, i installed new intake and it gets worse

it happens in 2 ways

1. when my A/C is off, during accelerate from stop.. but it goes away within 5 sec

i do have that new hissing sound from intake, but it new baby hissing sound..

its like high pitched electrical sound

this sound is not that loud, but still noticeable with window open

and when my rpm jumps(explained above), it gets louder and i can hear it clearly

2. when my A/C is on, i can hear hissing sound through vent as i accelerate from stop, and it goes away in 5 sec

but i can hear it again if i push the gas slightly, but it goes away once i let it go

but during heavy acceleration, i cant hear it

also when rpm jumps, i can hear this hissing sound through vent

i checked my local dealer, they said something on expansion valve is blah blah.. well, ill get a new part installed tomorrow, but i know its not A/C problem

local shop said some air vent under dash is bad.. i dont think so..

im sure avg. mileage went up a little with exhause and intake mod in most of case, but i just noticed mine actually went down a little

i tried to figure it out whats wrong for few days, but no bite..

i checked muffler, its not installed backwards.. and it doesnt have any leak

possibly MAF sensor on intake tube might be messed up during new intake installation, but i dont get any error code

#16,17,18,19,20 on this thread

i saw guy at muffler shop cut that thing when he install new muffler

what that thing do exactly?

vacuum leak? iac motor? belt?

and more!

i was gonna just drive since is not that loud it but it started bugging me now

tried to pinpoint this for a week now.. cant really think of anything.. everything seems just fine..

any thought on this?

appreciate it in advance

whoever pinpoint it exactly will receive small gift from me!!!!!!!

its 2005 4.7L by the way


double posted on JU.. sorry if someone mind double posting ;)

Jeep Brian 07-20-2007 09:48 AM

My 318 Dakota did the samething after I installed a M1 intake, KN filter charger and a jacobs pro street ignition. Truck would run really funny if I undid the battery and then reconnected and started it. I think the engine is just trying to learn how to run with more air getting in and out. It has to learn everytime something else is turned on ie. a/c on and no a/c. It might take some time for it to learn everything. just my .02

miq228 07-20-2007 03:41 PM

yeah i thot about that too

its benn 4~5 days since last battery reconnect

4~5 day isnt enough?

ill give few more days

thanx for the input!

Jeep Brian 07-23-2007 06:37 AM

It has to be something with the intake kit. I wonder if MAF sensor is just bad. I would not think that it would go bad at the same time you place a new intake tube on, but I guess anything is possible.:confused:

ParoxysM 07-24-2007 07:28 AM

I have no issue with my setup. I don't hear the K&N until about 4k RPM

soldierguy 07-28-2007 09:06 PM

It can't be a MAF sensor...WKs have no MAF sensor. Ours work off of a pre-programmed fuel map that determines how much fuel to inject based on a variety of other sensors (engine RPM, road speed, throttle position, gear selection, O2 sensors, knock sensors, etc).

That said, I'd look at your O2 sensors, as well as the intake air temp sensor just after the air filter. That might be your issue. Perhaps they didn't get plugged in all the way after the installations, or during the installs they were damaged.

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