I need some input. At high rpm's my 4.6 coughs an d chokes. Could this be a clogged fuel filter or possibly a fuel pump? Any ideas?

 

trixman,

At what RPM exactly does the engine do this? In what gear? You may be at the upper limit of the rev limiter. How many miles on the truck?

Regards

Jean Marc Chartier

 

there is 470000 miles on the truck. The coughing happens under hard acceleration in first gear around 5 grand. This problem has just started within the last week.
Chris

 

A half a million miles on a newer F-150?? I'm sure that was too many 0's . Just following up for suggestions 'cause mine's been having a similar problem for that last several days. Fuel injector cleaner in the gas tank didn't do any good. (I'm @ 81,000 miles)

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'97 F-150 Lariat Ext. Cab 4X4

• White/Silver
• 4.6L, Auto.
• Tinted Windows/Bedmat/Toolbox/Lund Bug Deflector
• 265/75/16 BFGoodrich on polished 16x8 AR-136's
• Cat-back Dual Exhaust
• Polar Bear Grille Guard

 

Well, my coughing spell turned ugly. Didn't think I'd make it home at lunch it was running so badly at every speed (except idle). The check engine light also came on and wouldn't go back off. It's in line at the shop to hook up to the scope. Will let you know what happens.

 

Had you washed the engine down or driven through a deep puddle recently?
Plug wires with water are not good.

Resetting the EEC often clears a bogus adaptive table that is screwed up by some erroneous input.

Glad to hear it is better.

birdman

 

I never even thought about that big puddle I drove thru last week. I will check into it when I get home. Thanx
Chris

 

$105 for the scope did no good, except to tell me there was a misfire. Ran just as bad when I pulled off the lot. Put new Motorcraft plugs/wires in Sat. morning (4 hours) with the battery disconnected. It's running perfect so far.

 

If you were asking me, no. No I haven't washed it or anything. Hasn't rained in I don't know how many days either.

 

Reset the computer and checked the plug wires (new plug wires 3 months ago) revedthe motor and power-braked it up around 3500 with no problems. Went out on the street and the darn thing coughed, spit and sputtered. This problem is buggin' me. Could it be the coil packs? the crank trigger? fuel filter? injectors? any ideas are most welcomed

 

To answer your question, yes, a filter or the pump can cause this.

I would look into an SBDS diagnostic. If there are any codes stored, the codes will narrow it down. Usually, in this situation, if the problem is electronic, the check engine light will come on. EEC V will detect a "hard miss".

SBDS is the only way to pintpoint the problem through a logical process of elimination. If the problem is intermittent, the flight recorder will allow you to capture data as the miss occurs.

Hope this helps.

Crash



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