My new (to me) 02 996NB has an odd, non-linear response when I step on the gas. It happens in many situations, but most noticeably at highway speeds. When I add light throttle there is a very slight hesitation and then it's as if I gave the pedal a much harder push - the car jumps. It's like an on/off switch instead of a smooth linear response to the pedal input. I suspect this is related electronic intervention in the throttle application process, but it sure is annoying. The pedal action is smooth and the car is bone-stock (not for long) with 15K miles on it (not for long). Anybody have a similar experience and/or solution? Thanks. <JM>

 

Is it kind of a sticky / gritty feel? If so, I've done a write up on how to take the pedal apart and clean everything. Do a search for threads started by me.

 

...sounds like a candidate for the Sprint Booster!

 

Sounds like a stick throttle body...... try cleaning it!

 

I think I know what you're talking about and they all do that. In certain situations there is a little jump that has something to do with the drive by wire system. I know one guy that didn't believe me and traded his car back in because of it. Agreed that its a little annoying, not sure what can be done about it. That sprint modification looks interesting, but I don't really "get" it. It might give a more progressive feel in the situations you are noticing.

 

See if it happens as you accelerate through 3200 rpm. If that is what you are describing, it is a shift in the camshaft timing and is normal. You get used to it after a while and don't notice it anymore.

 

i have it too on my 02 c2! i knew it wasnt my clutch.. glad to hear it's normal!

 

I have an 2004 and it has this little, and I mean little, step. I have no other words for except that it feels like there is a slight hesitation or change in engine performance right at 3100 or 3200. On mine it is not really a jump, just a very slight change. Have I confused everyone now?
Tony C

 

Thanks for the inputs. This is definitely not a variocam related change, as it happens at various RPMs. I'll try cleaning the throttle body and MAF to make sure those are not the culprits. The car sat a lot (14K miles in 7 years) and it could well be that something is gummed up. I've now read enough forum history to realize there's a known drive by wire issue (thanks Darren), but it seems more extreme than most. I'll follow up after I do some cleaning. Did anyone try the Sprint Booster? I'm curious whether this defeats the built-in throttle lag... <JM>

 

i am going to try the SB as soon as I get my car. Here's some real-life info/observation for you on engine lags and general acceleration malaise, etc:

In a previous life I bought a 50K miles, 95' 993 6-spd from a local lady that barely drove it and never exceeded about 3K rpm. (When I test drove and pushed it to 6K + she went apoplectic and almost died on me). Anyway, I had a strong feeling that the engine needed an Italian-tune up and more since it was very doggy, but had good bones. Anyway - sensing that the cat was clogged after I bought the car I took it to my buds at ASG and they looked at the cats with an IR temp sensor and noticed that one side was noticeably hotter than the other (993 has two sides to essentially a cylindrical cat assembly). No problem, I happen to have a spare cat ***'y and swapped it out in a jiff - well, maybe 2-jiffs. Car ran remarkably better but was still, very slightly -doggy - how do you say: woof??? So my next step was to buy 2 cans of SEAFOAM from the local auto store and went to work. Essentially, I was able to comandeer a vacum port to the intake system and over period of about 5 minutes, introduced an entire can of Seafoam into my already-warmed-up and idling 993 intake system. Shut it off and let it sit for about ten minutes and then started it up again recognizing that the can said it might 'smoke a little'. Folks - the whole neigborhood was pretty much instantly covered by a thick beautiful white cloud of smoke as I choked and sputterd down the road. (Thank heavens for private neighborhoods) Once I got the system cleared out of, not only seafoam, but intake system GUNK, the car ran like a turbocharged, pissedoff bat out of he**. And it continued to run like that until I sold it a year later. Moral of story: Seafoam works - it's cheap - it's easy to administer - and if you have a crappily-running higher mile or molly-coddled 996, it may help. Anybody used Seafoam in their 996??? Maybe the water-cooled P-cars don't respond to seafoam like the air-cooled bretheren??? Actually, when ASG and I were previously discussing the 'dogginess' they suggested an engine flush. I did my research and 'foamed it and never looked back. The stuff is amazing my .02 cts worth. No affiliation, yadda-yadda-quack-quack.