What's behind loss of power?

[PAExplorerXLT]

My 98 Explorer XLT has developed a symptom. It feels "out of breath", meaning it doesn't accelerate well and can barely get above 60mph even if you floor it. Then there is the booming sound when you open the throttle. Sounds suspiciously like muffler noise. The engine is also rough at idle. What these add up to I don't know.

 

[Centaurus5.0]

Sounds like your fuel pump is dying. Booming (popping?) sound could be misfiring/backfiring from lack of fuel.

 

[PAExplorerXLT]

I hope you are right. Is there a definitive way to test for it? How big a is a fuel pump job? Interestingly, CEL is off.

 

[Centaurus5.0]

http://troubleshootmyvehicle.com/ford/4.0L/how-to-test-the-fuel-pump-2

Not a bad job. There are many how to threads on here and youtube. Having a buddy to help lower the tank helps.

 

[96eb96]

My 98 Explorer XLT has developed a symptom. It feels "out of breath", meaning it doesn't accelerate well and can barely get above 60mph even if you floor it. Then there is the booming sound when you open the throttle. Sounds suspiciously like muffler noise. The engine is also rough at idle. What these add up to I don't know.

Could Be exhaust blockage too. Diagnose properly before changing parts.

Get a fuel pressure gauge and monitor pressure.