89 Bronco 5.0 stuttering/misfire issue

Hey hows it goin, so long long story short i unfortunately have a 89 fullsize with 5.0 and around 170,*** miles on it and over a period of 2 years have been dealing with this problem and its driving me crazy, so the best way i can explain the problem is if i rev it up at idle it stutters then revs up fine once the rms get past 1200 if i slowly rev it up its fine. But it always idles great and drives down the road great but as soon as i try to give it any gas at all it just chugs in spits and pops like the timing is off but runs great once it gets over 2000 rmps. So thats my issue now for the list of things ive replaced so far, the tps sensor the o2 sensor plugs wires msd cap new distributor pigtail and module new inline fuel pump(frame one) ecu put Ford motorsports headers removed catalytic converter and smog pump. Only things left to change are distributor map sensor and fuel pressure reg but really really ungodly fed up with throwing parts at it with no improvement also if i unplug and plug in the pressure switch to the power steering pump it acts like its loading down the engine and lowers the idle which i cant explain. .

Any help would be much appreciated! !! Thank you for your time

-Josh

jjwhitis88 said:

Hey hows it goin, so long long story short i unfortunately have a 89 fullsize with 5.0 and around 170,*** miles on it and over a period of 2 years have been dealing with this problem and its driving me crazy, so the best way i can explain the problem is if i rev it up at idle it stutters then revs up fine once the rms get past 1200 if i slowly rev it up its fine. But it always idles great and drives down the road great but as soon as i try to give it any gas at all it just chugs in spits and pops like the timing is off but runs great once it gets over 2000 rmps. So thats my issue now for the list of things ive replaced so far, the tps sensor the o2 sensor plugs wires msd cap new distributor pigtail and module new inline fuel pump(frame one) ecu put Ford motorsports headers removed catalytic converter and smog pump. Only things left to change are distributor map sensor and fuel pressure reg but really really ungodly fed up with throwing parts at it with no improvement also if i unplug and plug in the pressure switch to the power steering pump it acts like its loading down the engine and lowers the idle which i cant explain. .

Any help would be much appreciated! !! Thank you for your time

-Josh

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Hi JJ ... , all that sounds me like a "to much open exaust with OE cams..." , did you tryed to replace his original  exaust sistem (totally) ? or you have just removed da headers ? (i miss this point)

Ya ok that makes sense i have headers into one 3" no cat into a 10 series flowmaster with side pipe

With stock cam

jjwhitis88 said:

With stock cam

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Maybe that's da problem... . The muffler is ok...but with all the rest you lose too much power "down side" . i understand its expansive just try to come back plus we all love a good sound ...but streight pipes needs new cams .... my 2 cents. Good luck man , i really hope u'll resolve

Cool thanks man ill look into that, another issue i have is its not advancing the timing enough with using a timing light its only advancing to the 20 mark from the 10 degree mark when i plug the spout in have you ever herd of this before?

jjwhitis88 said:

Cool thanks man ill look into that, another issue i have is its not advancing the timing enough with using a timing light its only advancing to the 20 mark from the 10 degree mark when i plug the spout in have you ever herd of this before?

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http://www.fullsizebronco.com/forum/showthread.php?t=168214   . That's all i can personally give you     >-

Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.
Your engine and transmission are computer controlled.
The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.
Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.
Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.
Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.
SO here you go...
How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway

HowTo Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more

You might also want to check your IAC

HowTo check your IAC
http://www.fordforumsonline.com/forum/engine-drivetrain/261-howto-check-clean-your-idle-air-control-valve-iac-iab.html
http://www.fullsizebronco.com/forum/showpost.php?p=3455850&postcount=6

Thx but already hooked it up to a code reader theres no codes its just not advancing timing enough when i accelerate causing it to sputter and miss thinking its the distributor just replaced the map sensor yesterday with no change. But if i unplug the timing spoute it drives great

Hey JJ,

As Joe said the comp. controls the engine. If you had a sensor problem, it would be giving the comp. readings out of the accepted perimeters, and set a code. If you have no codes I doubt that there is a sensor problem.  OR you have removed some of the emission control equipment and the comp is in a constant open loop condition. Does your CEL light come on in the KOEO position? 

Do you know the fuel preasure at off idle, when the engine is actually studdering?  Does that condition occur in park or only when driving and putting the engine under load?   If only under load the most likely culprite is the secondary ignition.

Good luck

jjwhitis88 said:

Thx but already hooked it up to a code reader theres no codes its just not advancing timing enough when i accelerate causing it to sputter and miss thinking its the distributor just replaced the map sensor yesterday with no change. But if i unplug the timing spoute it drives great

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yo Jdid the scan tool go through both KOEO & KOER tests? or did it fail to begin & complete?

re your, " if i unplug the timing spoute it drives great..."

Shudders, Bogs, & Intermittent No-Spark:

Spark w/SPOUT Connector Un-Plugged, but No-Spark w/SPOUT Connected, due to distributor, in a 93 & KOER test won't begin; "...The engine starts to bogg down and then it shudders before it downshifts and smooths out. (example, when rpm’s drop going up an incline it will shudder for a few seconds before the rpm’s increase and it drops out of OD). If I remove the SPOUT the shuddering downshift problems goes away; then, when I replace the SPOUT the shuddering downshift problems comes back; Distributor was causing the problem..."

Source: by buck45 at Ford Bronco Zone Forums

Troubleshooting Tips, Distributor-Mounted "1. Verify charging system operation; specifically, charging voltage. 2. Verify ignition system operation; specifically, there are no open or disconnected plug wires. 3. Remove distributor cap and inspect connections where TFI module hooks to the Hall Effect Switch connector. If there is any sign of deterioration at the connector, the Hall Effect pickup must be replaced. Crankcase vapors are forced into the distributor due to excessive crankcase pressure due to a worn engine or an improperly maintained PCV system. The crankcase vapors cause deterioration of the insulation around the connectors causing the module to short out."

Source: by niehoff.com

Consider Ford Fuel Injection and Electronic Engine Control: How to Understand, Service and Modify, 1988-1993; & Ford Fuel Injection and Electronic Engine Control: How to Understand, Service, and Modify All Ford-Lincoln-Mercury Cars and Light Trucks, 1980 to 1987 by Charles Probst

avail @ BARNES & NOBLE, AMAZON, E BAY, ETC.