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acceleration issues with 99 vw passat

11K views 19 replies 8 participants last post by  mrgreek2002  
#1 · (Edited)
just recently my wife's passat started having problems accellerating both from dead stop and from a corner. she'll give gas and it starts to choke/sputter for a little bit then finally starts to accelerate(occasionally the car will stall). it's gotten more noticeable over the past month. we've had the plugs changed, the wires changed, fuel filter changed but i still can't figure the damn thing out. i've added fuel additives to clean the injectors. what it reminds me of is bad timing, but we had that looked at as well. any known issues with the passat similar to this?

any suggestions are most appreciated.

99 passat 1.8t
108000 miles
recently had plugs air filters changed. fuel filter not changed.

p.s. i've tried looking for the mass airflow sensor to disconnect it but i cannot seem to find the darn thing.

Thanks!
joe


**update**

ok, was able to get the codes.

P0103 MAF or VAF a circuit high input

P1127 Manufacture control feul air metering.

per chiltons P1127 means running rich.

I'm still running real bad after having disconnected the MAF for a little bit. I've checked all of the vacuum hoses for leaks and couldn't find any. I'm currently trying to test the fuel pressure but i'm stuk because I cannot remove the fuel line. the clamps a re bit tough to undo. any advice? the only tools I've got atm are a pair of needle nosed pliers. thoes are the only things i can get near the fuel line to try to undo the clips. (btw thw spot I'm trying to tets is where the rubber fuel line meets the metal line near the firewall.)

**update6/9/09**

ok the lurching has ceased after i replaced a couple of bad vacuum lines, however, the car still stalls when coming to a stop. the only thing i can do to stop from stalling is to tap on the gas real quick. my f-in-law changed the fuel filter and said in his 30+ years in the business he's never seen a filter so clogged. i disconnected the MAF and still have the same issues, i'm wondering now if it's a fuel line/fuel pump issue. any way to diagnose that easily?

Thanks!
ras.
 
#3 ·
timing belt = next month, but it did not break if that was the question.

vacuum hoses?

M-I-L? I couldn't tell you anything about that. I don't even know how to get the codes out. I'm thinking I should probably get the manual from autozone because i' m not sure where to start with the hoses or getting teh codes.

i do have a feeling that the fuel pump could be going out. my father in law looked at the fuel lines (he's a mechanic) and said they were terribly dirty(lots of deposits). unfortunately he doesn't work with vw's too much so he couldn't find the fuel filter to see what that looked like. can anyone tell me where to look? i looked behinnd the right rear wheelwell but i couldn't find anything.

help?1!

thanks!
joe
 
#4 ·
How on earth can you look at the fuel lines and determine that there are lots of deposits?

You need a VAG-COM. Even if your Check Engine Light (CEL, or MIL) isn't on, the ECU stores codes that can help troubleshoot. Autozone willscan your car for free, but it's a generic OBDII scan so the codes have to be interpreted.

Absent a VAG-COM scan, first best guess would be cracked vacuum lines. Pop the hood and look at them - if they are fabric-covered, then they are the original lines and no doubt need to be replaced.

Other possibilities that are more likely than "dirty fuel lines" are a clogged fuel filter or a dirty throttle body. The fuel filter is underneath the car, in front of the passenger side wheel well. You have to take the "aero" cover off the beam axle to get to it.
 
#6 ·
The Fuel filter is just infront of the rear, passenger side wheel. Like Rusty said, there is a cover there that spans the width of the car that has a stretched "U" shape to it that you'll have to remove to see it sitting there. It's attached to the inside of the wall.

Hope that helps,

~Epyon
 
#8 ·
^^^LOL!!!

IIRC there's a fuel-filter replacement write-up or two in the Info Forum. With pics, even.

The bad thing is, you can get into a lot of parts-swapping trying to track down the problem.

The good thing is, you can get into a lot of parts-swapping trying to track down the problem - with as many miles as you have on the car, even if it doesn't fix the problem, you probably needed it for maintenance anyway.

And with 108K, if you haven't replaced the timing belt yet, the car is a multi-thousand-dollar repair waiting to happen. Get that done ASAP! The '98's and '99's are especially vulnerable, because they have a tensioner that's a really crappy design.
 
#11 ·
I know the TB change can be costly but the cost will be really high if it snaps as Rusty stated. I wish you the GL with the month or so wait and I hope for your sake it does not go before that. It is an intimidating job to DIY so find a good Euro Indy shop because you can save big $$.
Obviously you need to solve the issue at hand but I would make the TB a top priority as well.
You may find this link helpful:

http://www.roadhaus.com/shops_advanced_search_results2.php
 
#14 ·
I'm still running real bad after having disconnected the MAF for a little bit. I've checked all of the vacuum hoses for leaks and couldn't find any. I'm currently trying to test the fuel pressure but i'm stuk because I cannot remove the fuel line. the clamps a re bit tough to undo. any advice? the only tools I've got atm are a pair of needle nosed pliers. thoes are the only things i can get near the fuel line to try to undo the clips. (btw thw spot I'm trying to tets is where the rubber fuel line meets the metal line near the firewall.)
 
#16 ·
Make sure the air intake snow screen is not plugged and that the air filter is clean. The throttle body should also be cleaned and then aligned. You can also clean the MAF. I would look for someone with a vag-com to run a MAF flow test if it is still a problem after that.
 
#19 ·
sorry it took so long to update with my solution, as pretty much everyone stated, the MAF was the culprit. I purchased a new one from the dealership, and as soon as I replaced the old part and turned the key (of course after making sure all the connections to the ICM are nice and tight since the car doesn't start if you don't :whistle:) she started running like a champ. I can't believe, such a simple looking part could be behind such a frustrating issue.

thanks again for all of your help. my CEL went out without having to reset it. boy does it feel good to have this car back to reliability.

:thumbup:to all of you for your great advice.
 
#20 ·
:thumbup: I had similar issues in later 2001 / early 2002, my car was in a body shop for 6 months and the MAF was somehow fouled from all the paint fumes in the shop. I drove it like that for a couple months, then one day it fixed on it's own (must have cleared out all the fumes with all the 'racing' I was doing ;)). I did go to the dealer once and they said it was the MAF and I told them that the car has been in the shop for a long time, so this is probably why, they said I was crazy, who's crazy now! Saved $600 + tax + labor to install the darn thing! :D