running real rough

[Zev221]

I got a 92 bronco with a 351 v8, automatic, when i start the truck it starts fine and idles untill i touch the gas, if i rev it then take my foot off the gas the truck starts to idle very low, when im driveing around it feels like it miss firing, its running rich the smell of gas is very potent, if i slam the pedal down the truck accelerates very slowly but the rmps run high, i thought it was mis-firing so i replaced the spark plugs, wires, distributer cap and rotor, ignition coil, and the o2 senser, its still running bad, any sugetions?

 

[miesk5]

yo,

First try a Self Test for Codes by my pal-in-tools, BroncoJoe19

do the KOEO = Key On Engine Off portion first & Remember to have engine @ Normal Operating Temperature before doing the KEY ON ENGINE RUNNING (KOER) portion

Post Code(s) found here by:

KOEO:

KOER:

Check plug wire routing;

Misfiring/Pinging due to Improper Spark Plug Wire Routing for 5.8

Are plug wire routed as shown on rad decal?

Misrouted spark plug wires can cause a misfire or buck and **** under load.

Spark Plug Wire Routing & Firing Order TSB 94-04-10 for 87-93 5.0 & 94-96 5.0 & all 5.8 - engine miss, spark knock, buck/***** surge and other driveability concerns;

Pull a few plugs and look for a lean condition = intake man, EGR Valve , throttle body gasket, Vac Leaks, bad Fuel Pressure Regulator (FPR) or weak fuel press from Pump.. Pull red vac line from FPR - any gas or gas smell = replace da FPR

Disconnect the vacuum line going to the fuel pressure regulator. Fuel pressure typically jumps to 40 PSI ± 3 PSI (4.9L typically is 15 PSI higher). can get into PSI testing later..

Rich plug = O2 sensor /conn/wiring etc prob (should have a Code in KOER), ECT Sensor prob (code too)

Spark Plug Firing End Analysis, General Source: by gnttype.org @ http://www.gnttype.org/techarea/engine/plugs.html

Over-advanced ignition timing can cause a misfire or buck and **** under load. Pull SPOUT Connector and time it

Adjustment in Ford EFI Engines

Source: by Ryan M (Fireguy50) at http://fordfuelinjection.com/index.php?p=71

 

[brody]

hey dude just bought a roughed up 89 3 months ago and fixed the same problem on my 5.8. rough idle, smelled gas, extremely slow acceleration blah blah blah. i did everything from emptying the cat to replacing pretty much all sensors. Try to unplug and seal from the vacuum from the manifold to the map sensor. if you can trick the computer into giving you a better idle and a little better acceleration then its probably clogged or damaged fuel injectors. thats what mine was anyways. let me know how it works for u. i just finished today and now my b@#$ is pulling tires on the pavement. Ahhhh it feels good after 3 long months of self false diagnosis hahaha. Oh yeah and how did the problem start if that doesnt work.