My truck is running rough at times and I keep getting stuttering/occasional rough or missed shifts.
Any help would be appreciated

The O2 sensor was replaced in March because of HEGO sensor codes but I forget which ones exactly. The exhaust pipes were replaced including a new three-way cat and new muffler(all OEM)
My AIR pipe from the cat is hooked up too.





Codes(Definitions taken from Ford Fuel Injection site):



173<table class="MsoNormalTable" style="border-style: none; border-collapse: collapse; width: 452.5pt;" border="1" cellpadding="0" cellspacing="0" width="504"><tbody><tr style=""><td style="width: 26.95pt; border-width: medium 1pt 1pt medium; border-style: none solid solid none; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; padding: 0in 5.4pt;" valign="top" width="36">
</td> <td style="width: 513.5pt; border-width: medium 1pt 1pt medium; border-style: none solid solid none; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; padding: 0in 5.4pt;" valign="top" width="545"> HEGO sensor circuit indicates system rich (right side)
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179 Right side still rich, at leanest adaptive limit, during part throttle.


628 Converter clutch Lock-Up error (E4OD)


634 <table class="MsoNormalTable" style="border-style: none; border-collapse: collapse; width: 452.5pt;" border="1" cellpadding="0" cellspacing="0" width="504"><tbody><tr style=""><td style="width: 26.95pt; border-width: medium 1pt 1pt medium; border-style: none solid solid none; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; padding: 0in 5.4pt;" valign="top" width="36">
</td> <td style="width: 513.5pt; border-width: medium 1pt 1pt medium; border-style: none solid solid none; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; padding: 0in 5.4pt;" valign="top" width="545"> Transmission Manual Lever Position Sensor circuit out of self test.
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I would assume your fuel mileage is not so good too? I suspect the Fuel Pressure Regulator is bad. Pull the vacuum line off of it, check for signs of fuel by smelling it and visually by looking for raw fuel. Well known cause of poor fuel mileage and rich codes is a ruptured diaphragm or the FPR is allowing too much pressure.

 

My fuel mileage is about 16-17MPG reliably right now.

I replaced my Fuel Pressure Regulator about three weeks ago with a new one, I believe it was BWD brand and it stopped a lot of near-stalls I was having(usually when driving about 15 miles to work and putting it in reverse to park)
I will check that though next time I head out.

I also need to re-check my timing since I followed a small guide(Replace plug wires with ones that would be overkill, gap out spark plugs, replace coil with hotter coil, then bump the timing up a bit). I know right now that it's below 14 degrees and above 10 degrees and it holds at a nice smooth idle, I just have to crawl under and mark my timing marks again and break out the timing light.

 

Well that blows that theory. I have done the "sixlitre" tune up on my '92 F-350. I picked up a MPG or two. Have you cleared the codes since you replaced these parts? As far as the shifts go it could be a bad TPS. It may have a bad spot on it or non linear. Many times there is no code displayed.

I checked mine last week with a DVM. I attached the meter then slowly pushed the throttle through the entire range of motion while monitoring the display. It tested okay, but in the process of attaching the meter I notice a nasty build up of green corrosion in the TPS connector. Cleaned it out, applied some dielectric grease, so far so good.

Another cause of poor mileage and lean/rich codes is the MAP sensor. Again it may not be bad enough to trip a code, but if it is not putting out the correct signal the wrong amount of fuel may be injected. I would suggest to test it too.

 

Yeah, codes have been cleared by a scanner and by leaving the battery unhooked for 6+ hours(different times) and they keep coming back.

My old red covered Haynes is confusing me though, I've not seen a device that looks like a voltmeter and is called a Tachometer in any local stores, though I haven't scoured the ends of the earth yet either.

Any simple way to test a MAP sensor with a multi-function voltmeter?

 

Use a vacuum source to apply a measured amount of vacuum to the MAP, use a multimeter like this to measure the frequency output: Centech AC/DC Digital Multimeter

My hand held vacuum pump/gauge combo works great for this application.

 

I swapped the MAP sensor with one from a parts store(I know most of the people there, so I can take new parts back most of the time).

I re-checked it and left the battery unhooked overnight, seems to drive a little better so far and only code 173 came up when I drove but it popped up more frequently, about once a drive the past weekend but only when traveling 25-30MPH, in-town speeds

 

Hey, curious question.
Which way does a PCM on a '94 F150 come out? Through the cab or through the engine bay?

I know this is the last probable part, but I also just read that the capacitors will start to bleed out with age and heat and wanted to check on them/replace them before that turns into a problem.

 

The PCM comes out from the engine side of the firewall. Take out the 5 or so screws that hold the inner fender liner. Remove the PCM connector, then IIRC there is a bracket with two screws that needs to be removed. From there. slide out the box.

Your new exhaust....is it custom? 2 into 1? Is the O2 sensor in the stock location?

Other items that could cause a true rich condition is the ECT or ACT sensors. If either is still in range but sending a signal indicating the engine coolant or air charge is very cold the PCM will dump in more fuel. Ryan has the typical values of these sensors listed at Ford Fuel Injection.com.

Have you pulled the plugs to see if the truck is actually running rich? I am running out of ideas here!

 

The new exhaust has one larger pipe(Probably 3") run from the first exhaust manifold and has a pipe come off of and connect to the second exhaust manifold on the way down(4.9l EFI manifolds) O2 sensor is is right under the starter.
It was a walker OEM replacement from advance, it just bolted right up with a three-way walker cat and a OEM muffler.

Plugs look ok, looks like some tan light ash deposits but I ran cleaner through only two or three tanks ago though.
Nothing that won't scrape off of the plugs, and some of the ash is coming off the plugs in spots(about one spot on each electrode, the clean ashless spots are black as it gets) if you want I can post pictures.

Engine Coolant Temp sensor replaced back around Jan with all the snow, the same with the Air Charge Temp sensor.