Hello all. Long time no see. I finally picked up another mustang to replace my old 98 that got totaled. It's a 98 v6 5 speed, and I'm going to drive it as is while I start stripping my old one to move all the v8 stuff over. The new 98 has a few minor problems.

1. The tach is off. I don't know how far off as I have no reference. It shows around 200rpm at idle, and just over 2000rpm at 25 mph (GPS) in first gear. I have checked grounds, and all look good. I'm just not very familiar with these 3.8/T5 cars.

2. The speedo is off. Using my GPS as a reference, it shows 7mph high at 50mph, and 10mph high at 70mph. As far as I know, the drivetrain is 100% stock.

Any help is greatly appreciated.