Just installed h/c package with BBK/Lingenfelter 58mm TB on a 96 LT1 M6. Tune is by Ion at madtuner. Car was just dyno'd and is in great health with the exception of running a bit rich (around 12.2).

When I'm cruising at a steady speed in any gear at around 1800-2000rpm, there seems to be an on/off switch in the throttle. It takes very little pressure on the pedal to maintain speed but if you use just a hair too little throttle it's like you took your foot off the pedal completely...then you get back into it just a bit to maintain speed and it kinda jumps...then it starts all over.

Any ideas?

Thanks!

 

Can you run a datalog? What are all the mods done?

 

Don't have anything to run a datalog with...sorry.

Mods:
1994 LT1 block bored .030 to 355cid
madtuner tune
3 year old T56
Lingenfelter CNC'd heads
Lingenfelter 74211 cam
Lingenfelter/BBK 58mm TB
Lingenfelter/Edelbrock port-matched intake
EGR/AIR delete
Pacesetter LTs
Pacesetter ory
Borla "cat" back
March underdrive
Corvette TPS
Corvette MAF
Lingenfelter CAI
MSD 8.5mm
NGK TR55s
stock injectors (32lb FIC's on the way)
stock fuel pump
stock (vented) Opti
Just pulled 315hp/320tq on a Dyno Dynamics machine (very conservative...a stock '505'hp Z06 only pulled 387 on this machine)

I see you're in Spokane...you've got a great autocross club up there (Autosports Northwest)...under new management and doing very well. In fact, the Sand and Sage Sports Car Club (SSSCC) here in TC is holding our last two events of the season starting tomorrow and my main competition is a guy from your area...Mike Gregg...in a 240SX turbo that's very well set up.

 

Check the TPS voltage. If the voltage goes too low, the PCM assumes the throttle has been closed and cuts fuel for decel. The closed throttle voltage may be set too low, or their may be a dead spot on the winding in the throttle position sensor. Typically, setting the closed throttle voltage around 0.67V, seems to produce the most acceptable results.

 

We'll do. Thanks.

 

I see he has a Corvette TPS so would that make a difference?

 

The TPS is "universal".... there is no such thing as a "Corvette TPS".

 

Well, all I can say about the 'Corvette TPS' is that the guy I bought the setup from sent me a different connector to go into the TPS that I had to splice into my harness...he told me it was because the TPS was off a Corvette. Maybe I misunderstood, I dunno...

 

TPS off a Corvette or not, run the tests that Injuneer suggested.

 

As soon as the autocross is done this weekend! Thanks!