[quote=skeith5;599252]I have not tested the IAC, but will do that after I finish cleaning it. http://fullsizebronco.com/forum/show...&highlight=iac


I failed everything but the gas caps. The HC/PPM was way too high and the C02 was a little too high. I'd imagine the Cat is shot, would that cause driveability issues?
Only if it has reached the point of contamination that it's back pressuring. Wacked plug gapping doesn't help. There should be a permanent sticker under the hood, usually on the air filter cover, denoting stock gap. Get that (correct gap) out of the way.

Stock gap will produce stock H/C emmissions. Larger gap (assuming the coil & ignition system will support it, will reduce your HC''s. Until the gap reaches a size it can't support (miss), then HC's increase dramatically.

O2's past their prime can increase both HC & CO2. The Cat is supposed convert CO2 to CO & reduce HC's. You get residuals above acceptable levels when the engine is putting out more than it can handle. When new, it (cat) can handle a lot. As it's used (especially when being poisoned by a poorly running engine), it becomes less effective til it's pooched effectively. Many times accompanied by increased back pressure.

My HC last tested .01 PPM.(actually a little too lean). What octane are you using? If running other than 87, your asking to fail. Along w/ premature Cat failure w/ a stock engine. The ECU is attempting to maintain a 14.68:1 air/fuel ratio, based on 87 octane. Very few situations that would allow a higher octane use. Currently, your not one of those!

Is this a good excuse to buy one of them fancy MSD Distributors?
Your choice as to how the PIP gets replaced. Personally, I lean towards replacing the whole distributor. Don't forget the TFI. They share the same power circuit & ground, so this marriage tends to have one going soon after the other. These are great too, but a stock distributer will do. If your wallet will handle it, what the heck: http://www.performancedistributors.com/index.html

WHAT? The suspense is killing me!
Vac leaks come to mind. You definitely need to Seafoam your combustion chambers & use it to desludge your engine, then change tour oil. That will also reduce HC's considerably. Sludge & dirty oil stores HC's & so do C/C deposits.. And it's fun too. Make sure you wait 15-20 minutes before restart (combustion chamber cleaning).https://www.f150forum.com/f33/how-se...1991-a-31505//[quote]
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Thanks for the info! I'll try out the Seafoam and see what that does.

I am running 87 octane fuel and have a station here that doesn't add ethanol to it.

The truck seemed to run better today. Still a little hesitation but it felt alright aside from that.

 

Seafoam's good for hesitation (flat spots) & improved throttle response in general. Give it 15-20 minutes soak time for best results, then start up & blow most the crap out, then take it for a hard drive. Engine maintenance at it's funnest!

 

I don't know whats more fun, the fact that the truck will act like new or the smoke billowing out of the back for 5 miles. Either way it'll make your day, it made mine.

 

Unfortunately it didn't do much for the way the truck runs... The smoke show was cool and I'm tempted to throw some seafoam in there every once and awhile just for that...

 

If you added it to your tank also, as directed, it's not done w/ you (& your dirty little injectors) till the tank's empty!

As far as repetition, After initial desludgeing, if you switch to synthetic oil, additional use in crankcase won't be needed. Leaving use in tank, & combustion chambers, occasional. Personally, I toss in a small bottle of "Lucas injector cleaner" every 4-5 tanks. You will find a lot less combustion chamber deposits when you do use Seafoam for the C/C.