1998 Ford F-150 Truck runs rough, no power going uphill, bac

Tiny
SSTEPP63
  • MEMBER
  • 1998 FORD F-150
  • 6 CYL
  • 2WD
  • MANUAL
  • 160,000 MILES
This is my Dad's truck. It started running rough a couple weeks ago and has gotten worse. Replaced inline fuel filter, no help. Replaced both front OS2 sensors, no help. Mechanic tested catalytic converter and said that is not the problem. When you start out in 1st gear you can just barely push the gas pedal or it will bog down to nothing. Once into 4th gear it seems to run OK as long as it's a straightaway, if you hit a hill all power is lost. You get nothing when you give it gas. If you rev the engine in park it backfires. Any help is appreciated becuase he won't take it to the shop and I'm left trying to figure it out. He changed the plugs about 2 months ago.
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Friday, May 28th, 2010 AT 9:47 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
If it is backfiring through the exhaust, I would start by looking for vacuum leaks. HAs the check engine light come on? Also, have you checked fuel pump pressures?
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Saturday, May 29th, 2010 AT 12:54 AM
Tiny
SSTEPP63
  • MEMBER
Backfire is coming from the engine and not the exhaust. Check engine light is on. I could take it and have it checked free on the machine but it is running so bad I'm afraid to drive it far. I was just reading about the MAS and I think I'll check that in the morning. I don't know how to check the fuel pump pressures. I will check for vacuum leaks tomorrow though. I know I can start out replacing basics; plugs, plug wires, etc. I know so little about auto repair. Would a vacuum leak cause the symptoms I described?
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Saturday, May 29th, 2010 AT 1:11 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Yes, a vacuum leak can cause a backfire. It is common for it to happen. As far as the fuel pressure test, it is really easy. We have a video and directions on how to check it and the fuel pressure regulator. The only thing you will need is a fuel pressure gauge. Most parts stores will lend or rent them to you as well as a scanner. You may want to check that. As far as the fuel pressure, here are the directions and video. Watch the video and let me know if you have questions.

http://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Joe
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Saturday, May 29th, 2010 AT 9:25 PM

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