Are these any good?

http://www.ebay.com/itm/1996-1999-Buick-Riviera-High-Performance-Tuner-Chip-Power-Tuning-Programmer-/302325089318?fits=Year%3A1996%7CMake%3ABuick%7CModel%3ARiviera&hash=item4663fac426:g:MyYAAOSwKytZGlP0&vxp=mtr

What happens if I need to unplug it to pull a code? Will it revert back to OEM tune instantly for the minute I'm pulling the code?

Is it safe?

Sounds like B.S. to me. What do have, money burning a hole in your pocket? LOL.

Tanqueray and some time to burn. LOL

From their description: "It then safely optimizes the ignition spark advance, air to fuel ratios and transmission shifting for the ultimate horsepower and torque gains."

From their FAQ: "The module never overwrites factory data and always preserves your warranty coverage. If for some reason you remove the tuner, no one will ever know it was installed."

Only one of these statements can be true, and it's not the first one, so...

Stay away... Very, very far away.

AA wrote:

From their description: "It then safely optimizes the ignition spark advance, air to fuel ratios and transmission shifting for the ultimate horsepower and torque gains."

From their FAQ: "The module never overwrites factory data and always preserves your warranty coverage. If for some reason you remove the tuner, no one will ever know it was installed."

Only one of these statements can be true, and it's not the first one, so...

Stay away... Very, very far away.

IIRC it biases the signal from the AMM to trick the ECM or some such. My take: don't bother. If you make sure there are no vac leaks and the boost modulator on the SC is working, the loud pedal will give you a whole lot of 2 tons of running fun.

There is a product called an AFC (air/fuel controller) that adjusts the MAFF feed from the MAF sensor to trick the PCM into adding more or less fuel. I used one years ago, before tuning the PCM directly, and it worked well. Mini AFC is $150 from ZZP if anyone is interested.

There is also a way to advance spark timing by plugging into the IAT sensor wires using a $20 "Race Pellet", a resistor module also avail from ZZP... BUT you need to use a tuned PCM that can take advantage of the module, as the OEM does not command more advanced timing with cooler air in our cars, but it does retard timing for hotter intake air).

I don't see how the PCM could be "tricked" in the same way through the OBDII port, otherwise the 3800 vendors would likely sell such a product. Maybe on newer OBD with CAN-bus it's possible?