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MAF? MAP? TPS? Idk

This is a discussion on MAF? MAP? TPS? Idk within the General Help forums, part of the LSx Technical Help Section category; My 01 T/A acts like it's got the jitters or something. It jerks and jolts and hiccups like crazy at ...

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    Junior Member Z28dryva's Avatar
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    MAF? MAP? TPS? Idk

    My 01 T/A acts like it's got the jitters or something. It jerks and jolts and hiccups like crazy at low rpm, it lurches forward when you go from about 3/4 throttle to 1/2, it won't idle worth a crap with the A/C on, and it wants to idle too fast and hang rpms when the A/C is off. I really don't want to just start replacing stuff but it has no CEL so Idk what it's problem is. One time long ago it flashed a code about TPS voltage too low but it never came back and it has on 2 occasions flashed a idle faster than expected code. I'm leaning toward the MAF since the car has 204k and the thing might have sucked some dust in at one time and it has had intake cleaner splashed on it on accident. This seemed to get worse after I ran it at the track 8 times a few months ago. Any idea guys?

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    Start with the basics. Check your fuel pressure at the rail - should be around 58 psi. Has the fuel filter been replaced lately? Clean your MAF with CRC spray MAF cleaner. If the MAF fails it will throw a code.

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    Junior Member Z28dryva's Avatar
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    The fuel filter has never been replaced. I always ran the seafoam in the tank and didn't worry about the filter but changing it once would be cheap insurance. I never had a code for the MAF and it does run like absolute shit with the MAF removed so I guess it is doing it's job. I'll change the filter and go from there. Thanks for the help. I'll keep yall updated

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    When you unplug the MAF, the PCM "fails it" and calculates airflow based upon engine rpm, MAP and such. If it still ran like crap, it is not the MAF. This being said, I would still clean it as they have been known to cause problems when dirty. Has the MAF been modified in any fashion -- ported, debladed or descreened?

    The fuel filter is located under the car, driver side, in front of the rear axle. Easy to change, just wear eye protection as it will leak when you remove it. It's a good idea to bleed off any residual pressure before removing it by placing a rag around the schrader valve on the driver side fuel rail and depressing the plunger with a small screwdriver. Again, wear eye protection.

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    Junior Member Z28dryva's Avatar
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    Yeah I've done a few F body fuel filters and usually got doused with a gallon or two lol. It is de bladed but all 5 of the other cars I did that to just got faster and never had a spaz attack like this one does. It's getting kinda bad now especially in traffic. You hit the gas and it hesitates before it goes

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    Former Mopar Man 2002ssslp's Avatar
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    Check for a Vacuum leak also.
    My ride is a 2002 Camaro SS SLP #3296 with 30k, LTH, 3" Y, CME, Frost tune, K&N, ported TB, Blackwing lid, Bellows, MSD, Denso Iridium, and 85mm MAF, Bilsteins, Eibach springs, SLP strut brace, Adj. Panhard, TA Girdle, UMI, Pro 5.0, Nitto NT555
    My wife has a 2004 GTO with the rare SAP, 18" wheels, K&N Cold Air System, MSD, Ported TB, Frost tune, Denso Iridium, Flowmaster cat-back, 3200 Yank, 75k

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    Modifying the MAF throws off its calibration. Mine was de-bladed when we bought the car and I had an off idle stumble that was fixed by replacing the MAF.

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    Veteran 0rion's Avatar
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    Quote Originally Posted by 2002ssslp View Post
    Check for a Vacuum leak also.
    this is where I'd start......check all the hoses going into the intake for cracks.

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    Junior Member Z28dryva's Avatar
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    I just fixed all that PCV mess and I'm eventually going with a GTO valley plate to be done with all that nonsense. The MAF has been debladed for over a year and I'm just now having problems so I really don't think that's the cause of all this nonsense but I'll throw a stock one on there and see if it fixes it.

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    Junior Member Z28dryva's Avatar
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    Update: I haven't got to do much of anything but I was bored at work during break and we have a mass abundance of brake cleaner so I decided to spray around and check for vacuum leaks. I ended up unbolting the TB and seeing if the high pitch whistle noise I've been having lately could be the TB gasket. I found a nice big glob of oily mud behind the crankcase vent and the IAC passageway. Made good use of my brake cleaner and made the thing spotless. I have a lot less problem with the idle now but it's still lurchy and shaky in traffic. I hooked the old trusty scanner up to it and I viewed my live data. The TPS is solid wherever I have the throttle at. The MAP is pretty much the same and comes and goes with the hills in the road and such. The MAF seemed a slight bit bouncy but nothing too extreme. What does disturb me is how I just hooked my scanner up to a F body I am looking to buy and the rear 02s don't even appear on the screen. Mine are missing as well but I have a spot for them that either reads .01 or -.01. That is a bit concerning and even more disturbing is local people on facebook are complaining on my old tuner, that happened to tune this car, saying they are screwing up tunes left and right. I'll proceed to do the fuel filter and clean the MAF and perhaps run another MAF just to satisfy those suspicions but I'm leaning toward the tune being the problem.

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    Junior Member Z28dryva's Avatar
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    Update 2: (if anyone gives a shit) Got the MAF cleaner and used it. I haven't been in traffic with it yet but it does seem a bit better behaved. Just bought my wife a 01 Camaro and it's MAF is descreened, as is 2 of my buddy's cars and as is my 5.3 truck (can't remeber if it had one r not stock) and none of them behave in the manner mine does. The high pitched whistle is still there so I'm about to rip the intake off and see what's broke. It's coming more toward the front of the motor but it's nothing upwind of where the TB mounts to the intake. Extensive testing and detecting proved this.

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    If you run an oiled cotton gauze air filter -- like a K&N, the MAF will need regular cleaning. Oil from the filter coats the wires on the MAF and small particulate matter clings to them causing it to misreport airflow.

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    Junior Member Z28dryva's Avatar
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    This seems to have been most of the problem but I'm still gonna change that fuel filter just because it hasn't been done yet.

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    Good idea. I change mine every other year, which means it is only seeing around 2,500 miles between changes. Cheap insurance imo.

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    Spaz is My Mentor SMWS6TA's Avatar
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    Quote Originally Posted by pajeff02 View Post
    Good idea. I change mine every other year, which means it is only seeing around 2,500 miles between changes. Cheap insurance imo.


    I avoid using break cleaner instead I used carb cleaner when checking for leaks. Have you sprayed any around the intake yet?


    Common vacuum leaks are intake and the POS PCV set up. Most ppl miss the y splitter behind intake. The hoses crack at that spot to.



    Do you know if the intake has ever been off? It could be a bad or misaligned intake seal. Spraying carb cleaner around the intake while at idle can help isolate the area.


    Your IAC got gunked up because of the POS PCV system. If you're looking for a change you have a couple of options. Catch can and/or LS6 Valley Cover Tray mod.

    I would think about just replacing the IAC. If it's been mucked up for a while chances are it's not working properly.

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    Junior Member Z28dryva's Avatar
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    I took the intake off a year ago to make a new PCV hose. The Y was completely torn in half and wasn't even connected to the driver's side valve cover at all. The system is leak proof and it will suck your finger to the valve cover on the vent side. I'm already planning on using a valley plate out of a GTO so I be rid of all that nonsense. The valley cover with the built in PCV system is cheaper than the dealer replacement bullshit pcv tube. I can completely disconnect the pcv system and it still whistles the same. I'm almost thinking it's not a vacuum leak anymore. Idk what else could cause such a noise. It all started on a short road trip. I noticed it when I pulled over for gas and heard it quite clearly. It's stayed the same the whole time. It's been shaky for a while now even before the whistle started. Now it behaves better but the whistle is still there. I will say about the MAF cleaner that it made a night and day difference on my 05 Z71. The thing tears the tires off every time I get on it more than half throttle. It seemed to do it good.

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    Junior Member Z28dryva's Avatar
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    Well the whistling noise is some pulley on the front of the motor. Lucky for me I stood on my head and listened real hard cuz I found that my steam vent crossover has a leak in it FML

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