# Poor throttle response at low rpm.



## vwnut84 (Sep 24, 1999)

Car in question is an '87 Scirocco 16v. 1.8, and all stock. My problem is when taking off from an idle, the throttle response is crap, and the car seems to bog down. The issue happens hot or cold, and sometimes goes away. Once above about 2,500 rpms, the car runs great, it's just taking off from a stop.
When driving along normally, you'll come to a stop and it will idle just fine right at 900, and then within a few seconds you'll hear the exhaust note change, and the idle will drop to almost stalling or around 600 or so. Sometimes it'll be fine though. 
My fuel mixture is set at 10mA, and from what I can see, the O2 is working correctly. The timing is at 8 degrees BTDC. I've checked over my boots and all are crack free. The injector o-rings were new not too long ago. I was going to pull the injectors out and check the spray pattern to make sure I don't have a fire hoser. 
There is another issue that might be related, and it's when crusing at highway speeds, the car seems to surge just a little bit, but like I said, when I set the fuel mixture the O2 seems to be alive and well. Could I still have a bad O2 sensor? I wouldn't think that the O2 would be the cause of the bogging down low as it does it when cold (open loop). 
Any help is appreceated. Thanks!!


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## ziddey (Apr 16, 2006)

*FV-QR*

unplug the o2 sensor
how's the coolant temp sensor


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## salz2135 (Sep 18, 2006)

Is the problem present only when your driving under load, or does the motor have trouble responding even when you just pop the hood and actuate the throttle body?
I had a serious hesitation that is similar to what you're describing. I diagnosed everything, fuel pressure, ignition timing, vacuum leaks, etc. My problem turned out to be the very last thing I checked: CIS injectors! At low RPM, and thus low air flow, two of the injectors were just dribbling fuel, but at wide open throttle they would spray enough fuel for good response. 
I replaced them, and my throttle response was extremely good.


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## fabstaMKII (Sep 9, 2008)

*Re: Poor throttle response at low rpm. (vwnut84)*

As far as your throttle response issue..there might be more than one thing going on....as far as your idle dropping ...for me I replaced the knock sensor after finding cracks in the wire and what not..problem solved, idle no longer drops so far.....hope this helps GL


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## vr6touring (Jun 30, 2010)

*Poor throttle response at low rpm*

hey guys my 1995 vw passat GLX vr6 at low rpm when you put it in 1st and you release the cluch slow and in ingages the front end will hop or jerk forwerd untell I hit about 1500rpm do u guys know what this is?

THANKS


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## GTIspirit (Dec 13, 2002)

salz2135 said:


> I had a serious hesitation that is similar to what you're describing. I diagnosed everything, fuel pressure, ignition timing, vacuum leaks, etc. My problem turned out to be the very last thing I checked: CIS injectors! At low RPM, and thus low air flow, two of the injectors were just dribbling fuel, but at wide open throttle they would spray enough fuel for good response.
> I replaced them, and my throttle response was extremely good.


I second this. Every now and then I experience a similar situation, and when this happens and I glance down at the WBO2 gauge I see that it's very lean, around 16-17AFR. As soon as response picks up the AFR goes back to normal. I too suspect that my original injectors are sometimes sticking in such situation, though it is conceivable that the plunger in the fuel distributor is sticking from time to time, or that the KE-Jetronic module acts up. I think it's highly unlikely that the KE-Jetronic would intermittently act up, rather unlikely that the fuel distributor control plunger is sticking, and more likely that the CIS injectors are sticking closed, though it's also possible that the reason the injectors stick closed is not enough fuel pressure and hence the high pressure pump could be wigging out.


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