I have an 1991 Ford f250 with a 5.8L gas engine, it runs really ruff and will only stay running if u work the gas up and down. it will not idle or accelerate without bogging down and will die if I hold the gas steady. I have replaced the plugs, wires, distributer cap, rotar. all where showing sings of ware anyway. I also replaced the fuel filter, fuel pump ran a pressure check on the fuel rail and the pressure is over 30#. ran a vacuum test on the pressure regulator and it held at over 30 lbs vac for over 30 min. I am running out of ideas and any advise would help
Fuel pressure should be 35 - 45 psi.could have faulty tps sensor.could have intake vacuum leak or ignition timing valve timing off due to worn timing chain.do engine vacuum test replace all vacuum hoses bad leaking egr valve diaphram or gasket will cause engine run poorly.
SOURCE: 1983 Ford F250 will start but won't idle without holding down gas
Its a ford! its cold blooded!! give it a minute, or adjust your choke, idle screw or timing. c'mon dude- even I know that. -BobbyGirl
SOURCE: 1997 Ford F150 4x4 5.4L
I would take the truck to an autoparts store and have the fault codes retrieved from the computer. Most stores will do the scan for free. I would lean toward a faulty throttle position sensor, but that's just speculation. The fault codes should narrow the problem down. Hope this helped and best wishes.
SOURCE: 1998 Ford F-150 4.2 V6 starts and idles fine ibut bogs when step
i had a van do this same thing to a tee turned out to be a broken key pin in the harmonic balencer causing the timing to ****** replaced balencer and ran like a dream there is a crank sensor grid on the balencer when the key pin broke it trew the timing off
SOURCE: 98 FORD ESCORT ZX2
1998 ford escort sport engine started making a tapping noise and engine light started flashing. Had oil and water at normal level.
Car has 110,000 miles. Been serviced regularly!
SOURCE: Ford F150 engine backfiring, running/idling rough
I Have a 1999 ford f150 4.6 that back fires and is just running really ruff when idling alot of nack fire a sord of like a pulse going on what is my problem?
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Hi. I can not give you one answer. I recommend to test, verify and narrow the search. It sounds like the timing or air/fuel ratio is wrong. What diagnostic tests have you performed so far and what did you find? Has the engine light been on since this issue started? If so, have you pulled any codes. Those codes could be invaluable. Did you verify that the spark plug wires were installed in the correct firing order? If so, run a compression test to make sure there isn't a bigger issue. How does the engine start literally. Does it start quick and easy but as soon as you let the key go performance is poor? Its possible that a component the ECM monitors or controls isn't operating correctly. The ECM receives information from that Intake Air Temp., coolant temp, MAF, CKP and CPS sensor and much more. Their performance is critical to help with timing and Air/Fuel ratio. Remove and inspect the EGR valve (it should be completely closed). Verify that the exhaust back pressure isn't high. I may be getting carried away. Depending on what you have for tools, reply and find. Some of my requests may be things you can not do. Please take your time. Read what I wrote and let me know how you want to proceed. I will be happy to answer any questions. Good Luck.
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