1999 VOLKSWAGEN JETTA
119,816 MILES
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KASRAK
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hi there

I have a 1999 Vw Jetta (MK4) 2.0 GL, the car is in excellent shape, i have a feeling that the TPS is gone bad, i want to make sure im right, it would be appreciate it if you can help out. it is a standard car, so when shifting from 1st to 2nd i feel a hesitation or a bucking, this only happens from 1 to 2, also when the car is in neutral (idle) the RPM starts tripping, bouncing up and down (not that severe) but the car has never stalled yet!
i also have a feeling that im not getting good gas millage,

sorry hope i explained it good enough!

if someone can assists me please, is it the Throttle position sensor or something else?
thanks
kevin

Mar 2, 2013 at 2:52 AM
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HMAC300
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clean throttle plate with choke cleaner on both sides as well as iac hole. then have an auto parts scan for codes.
Mar 2, 2013 at 4:37 PM
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KASRAK
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Thank you for the respond. Just one thing the check engine light is not on!!? Still run a diagnostic?
Mar 2, 2013 at 4:58 PM
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HMAC300
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yes and check fuel pressure i forgot that gauges are available for rental from auto parts stores. and they can scan for free mos t of them.
Mar 2, 2013 at 5:03 PM
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KASRAK
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Ok I went to a mechanic shop, he ran a diagnostic and there was no codes, he also checked the throttle body and he stated that it was all good! But he did mention that the exhaust manifold was making noise, he stated that there may be a crack, he said this can be the cause!? I want a second pinion! Do you think that a bad exhaust manifold can cause these symptoms?

Thanks for your help!
Mar 3, 2013 at 12:51 AM
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HMAC300
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a cracked exaust wont' cause hesitation but should be fixed so fumes don't get inside car. check all your vaccum lines for leaks. is this a diesel? try cleaning tps with choke cleaner as they can get sticky if there is anything outside the throttle body itself. this could also be a transmission problem that is not showing up any codes. so you ;might have a trans guy look at it as well.
Mar 3, 2013 at 1:21 AM
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KASRAK
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It's gas not diesel! I went back to the mechanic. He did clean the throttle, but he also mentioned that the mass airflow sensor could be bad. He actually unplugged it, what was strange is no check engine light came on and the car didnt stall. He unplugged it while the car was running, he said if the mass airflow sensor was good the car would of stalled

Could the problem be the mass airflow sensor?

Thank you
Mar 4, 2013 at 8:11 PM
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HMAC300
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actully if he unplugged it the car would have went into openloop which the way it runs when cold. check for broken grommets or holes in stuff like that to valve cover etc as that would act like a maf. also check for holes in duct work to thrtottle body from air cleaner . Other than that withou looking at it i can't give an answer.
Mar 4, 2013 at 8:25 PM
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KASRAK
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Thank you for all your help. I went ahead and cleaned the throttle and The mass air sensor, it seems much better! I have one last question? I also want to clean the PVC valve/heater, is it safe to use throttle cleaner to spray it, or mass sensor cleaner, or it doesn't matter? Or should I just leave it, it a bit oily in there!

Thank you, you were extremely helpful!
Mar 6, 2013 at 5:18 AM
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HMAC300
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replace the pcv valve it doesn't matter what cleaner you use if you want to do that, but it should be replaced.
Mar 6, 2013 at 3:03 PM
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KASRAK
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Ok I called VW and they gave me price, since the PVC is attached to the duct boot I have to buy the entire thing. Now they said there is 2 kind, 1. Is for cold weather @$185 2. Is warm weather @$258....... Now I live in Canada (it's kinda cold :)) but car was made in Mexico, so I'm kinda confused on which one to buy?
Cold weather?
Warm weather?

Thanks
Mar 6, 2013 at 3:46 PM
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HMAC300
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they shod be able to tell you by vin number
Mar 6, 2013 at 6:27 PM
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KASRAK
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Great! thanks for all your help!
Mar 6, 2013 at 6:36 PM