Van bucking when accelerating

1998 FORD E-SERIES VAN
210,000 MILES • 5.4L • V8 • 2WD • AUTOMATIC
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ANDDOR10
  • MEMBER
  • 8 POSTS
When accelerating at around 35 to 45-MPH van starts to stumble mainly going up hills. It feels like a misfire, but it shows no codes. Initially I had a code on a misfire on cylinder 8. The coil seemed loose, so I tightened up a little. The code went away but the problem still exists.

Thanks for your input.
Oct 25, 2021 at 9:08 PM
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KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
There are two things that I have seen with this type of issue if it is not a misfire.

First is fuel pressure. We need to hook the fuel pressure gauge up and tape it to the window and drive the vehicle so that we can watch the pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The pressure should remain steady and not jump around by more than a couple PSI.

Next is to drive the vehicle in manual gears so that we can try and eliminate the torque converter from shuttering. If you have an overdrive button, try pressing it and see if the jerking stops.

If it does then we have a converter clutch slipping and it can feel just like a misfire.

Let's start with this info and go from there. Thanks
Oct 26, 2021 at 9:49 AM
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