I have a 2004 3800 na installed in my fiero using a 99 pcm programed by a guy on here. The problem is when I try to give it gas, the car will not move intill half throttle. It will revere up at idle . It is only when I put it in gear to move it. feels like it is laking power It had the drive by wire throttle body , but I put a 3800 supercharged one on it. Thanks
[This message has been edited by fierofan25 (edited 03-05-2014).]
The MAF calibration for the 98-older and 99-newer 3800 MAFs is not that different. Certainly not different enough that having the wrong MAF calibration in the tune would cause a problem like the op is describing - "car won't even move until you give it 1/2 throttle". Sounds like there is a lot more going on here.
Like one of the posters suggested - try unplugging the MAF and see if it runs better with it unplugged and advise. You could simply have a bad MAF sensor.
If unplugging the MAF does not change anything, next thing you should do is check fuel pressure. Let us know what you find (engine running and what it does when you give it throttle and it lacks power).
I just checked my records and I was told you had an 04 L26 with a 97 L67 throttle body and MAF. The PCM tune I made for you was based on a 2003 Grand Prix 3800 Series 2 N/A base tune with the MAF calibration set up to match a 97 L67 TB and MAF sensor - since that is the throttle body and MAF sensor you are using on this engine. So the MAF calibration should be correct for what you are using.
The EGR tube that connects the base of the EGR to the intake manifold is prone to cracking on these engines, causing a vacuum leak which can make the engine run very poorly (especially at idle). Finding a good used tube is going to be very difficult if not impossible since they are so prone to cracking. Getting a new one is the best option since they are not extremely expensive.
GM part number for the EGR to intake tube is 24508516.