1994 3.9V8 TPS Flat Spot

discorunner94

Member
Mar 26, 2020
10
2
04102
Hi All,
Have a 1994 Discovery with 3.9L and a problem I can’t figure. Seen a number of posts on it, but haven’t had any luck.

Truck was throwing a TPS code (17) and ran increasingly worse at certain RPMs under acceleration, but intermittently. Ordered a new TPS and put it in, but the flat spot is still there. Has good fuel pressure, tested a new mass airflow sensor, recalibrated the TPS and even swapped the ECUs to a spare (have read that sometimes that’s the problem). No dice. Runs normally for the first five minutes, then the problem returns. Fires up and idles like normal.

Any ideas?? As both the stock and replacement TPS had flat spots, I am hesitant to try another one, but have read sometimes the replacements are shot.