Rough running after tune-up 5.0 v8

[AlexVanEks]

Greetings fellow enthusiasts (and sufferers)!

I recently purchased a 01 (98-01) Explorer Eddie Bauer with the seemingly rare gem of a 5.0 V8. She's a beauty and couldn't be happier even with the 198k miles!

However. I was in line getting pizza and the dreaded check engine light came on. She was studdering like a fouled plug so I went for the check. Sure 'nuff, misfire #3. Attained plugs and wires (motorcraft, or is it motorcrap? Plugs and Napa Lifetime wires). All the wires were probably original or way too old and #3 had some meltage from the plug end. Broke#1 plug and left just the blasted threads, had to have it pro removed (after two days of cursing wjile heating and beating, impact gun, 2ft+ of breaker bar and a shattered EZ Out). 2-4 were a pain in the you know where, I think they were nearly original. #2 was so fouled there was no gap, and all were corroded badly on passenger side.
Driver's side also needed changed but they came out textbook perfect so I think it was a wall job at the dealership at some point. Also have done coil packs and the pcv pain in the butt to reach valve.

Now comes the fun part!
NO CEL and no codes to give
Running like hot garbage, very bad mileage (she said 8 mpg ) and loss of power uphill. I can't feel for sure if there's still a misfire, but my suspicion is something is still amiss.
The worst is running 35mph ironically, she shakes like she's gonna tear apart! Idle sucks too, especially in drive. However, 30 or 40mph are fine, makes no sense.

I have a suspicious rattle that sounds like a catalytic converter shield and a definite leak in the resonator between muffler and exhaust pipe. The louder the leaks, the more annoyed I get. Her running with my foot in her isn't too bad, weirdly.

Plans:
New air filter. Mines full of bugs
Clean MAF sensor
Try to find the @$#& exhaust leak and repair/replace
Fix the stupid sway bar endlinks that just isn't freaking attached on the driver's side

Y'all are a super big help and this forum has saved my butt so many times with my previous Expy that I had to join!

 

[shucker1]

My first step would be to make sure the plug wires are all going to the right places.

 

[Mbrooks420]

I'd not be running it with a misfire. It can be extremely hard on your motor, or damage your cats.

Are you sure you've got the wires correct? I'd pull both ends, and make sure they are seated. If that fails, I'd pull the plugs and look for signs of misfire.

 

[AlexVanEks]

I did check and double check the wires both when I was replacing (did them one at a time) when first replacing, and then again with the new coil packs. I'll have to check the plugs and see if any of them are messed up. I have at most 20 miles on the vehicle since this fiasco and as my only vehicle I don't have a lot of choice when I need to go somewhere :/

I have a feeling the cats are factory original so there's a good chance they're already FUBAR lol.

Thanks guys!

 

[Mbrooks420]

I ruined the cats on my escape by driving it home with a bad misfire. If your cats were bad, you'd have a CEL.

Maybe get a spark tester and test to make sure you didn't get a bad coilpack.

 

[AlexVanEks]

Vehicle runs a bit better with the new packs so there might have been some breakdown in there. Feels like my old expy that had the exhaust held on with c clamps, when a clamp would come loose (bought it that way, was an expy neophyte or wouldn't have bought it lol).
Air flow sensor and new air filter just got installed. Going to see if it helped. If nothing else it certainly won't hurt!

 

[shucker1]

Perhaps a 1\2 can of Chemtool B-12 Fuel Injector cleaner in the gas tank with a full tank of premium gas to help get the injectors cleaned out again?

I do it to mine every so often.

 

[AlexVanEks]

I just got in and washed up. Checked the 1-4 plugs. #2 was fouled but that plug took the abuse when I had to limp her onto the flatbed with the EZOut lodged in the #1 hole. Replaced the #2 plug and fiddled with the #3 wire. The metal sleeve is a smidgen too long but I got a solid fit (I hope). Took her for a spin while hailing a few hundred lbs of wood, was okay until about 15 minute from home, then cel flashed, then stayed on.
Did the check, 7+8 misfire. Checked the plugs and they were okay. Reseated the wires and hit the road after the 5 minute negative off the battery reset. All was good for about 10 minutes, cel flashed. Went off, stayed off, came back on, went off.
Read flashing is a misfire but it won't stay on to get a good reading!

TL;DR:
Wires are new, plugs are new, coil packs are new. New pcv valve, new air filter, MAF sensor cleaned.

Truck runs reasonably, idles a bit shaky. Gas mileage went from 7 to 15 on the screen. Excelleration is reasonable, a bit hesitant going uphill perhaps.

Plans:
+Premium gas
+ Big @$$ can of sea foam brand top engine cleaner. (Supposed to remove gunk according to the can )

Thanks guys!

 

[shucker1]

Perhaps you might think about doing a compression check to see if you might have something going wrong inside?

You also may try to put a vacuum gauge on it to make sure all is good up top with no leaks.

 

[AlexVanEks]

I have no idea how to do those I will have to raid the forum to find threads for it

I'm going out today to knock the edges off the metal sheaths of the spark plugs. Planning about 1/32" removal, maybe a bit more. The block is corroded to some extent, and the metal sheaths seem to prevent a solid fit.
My CEL has consistently been misfire and I think everything compounding isn't helping. I have a vacation in four days and I /need/ my truck!

 

[Mbrooks420]

I wouldn't think the sea foam would be needed, and I'd be Leary of doing it with new plugs. I always foamed mine before.

The compression tester installs just like a spark plug. Very easy.

 

[AlexVanEks]

Still have misfires on 7&8 :/ Reset the computer again, going to have to go for a spin and wait for the flash of the CEL again.

I'll have to acquire a compression test tool somehow.

Beginning to think I have fuel injector issues, although the problem jumped from #3 to #7+8 :/ I don't know if the crud the seafoam knocked loose is causing misfire since it's often erratic?

 

[shucker1]

Compression Tester; Gauge can be bought at Autozone or any parts store. Remove ALL spark plugs. Disable fuel pump by removing fuse in fuse box. You don't want that coming on during test.

Screw compression test gauge into each spark plug hole one at a time. Crank the engine over several revolutions so you get a good pressure reading.

Your looking for all pressures to be even or within 5% of each other. Normal pressure would be 160-180 PSI.

Low pressure on all cylinders would indicate worn rings. Low pressure between two adjacent cylinder may indicate a blown head gasket.

Low pressure on one cylinder could be a bad valve.

Wet cylinder test would be next for that "Hole". Drop in an ounce or two of light motor oil. Re test that cylinder. If the pressure increases that would indicate worn rings. No pressure increase would indicate worn valves.

 

[shucker1]

Vacuum Test;

This may help.

https://www.motor.com/magazine-summary/mastering-the-basics-reading-a-vacuum-gauge/#

 

[AlexVanEks]

You guys are so awesome! I'm going to give the compression check a try soon as I can get the kit. Harbour freight has one for $26

Pretty sure with 198,5k miles, an engine cleaning/rebuild is in order. I don't have any clue how to do that and it's wayyy above my shade tree mechanic pay grade.
We have a shop in town but I have no idea how long it might take and I'd be looking at probably $1000 for a rebuild on a $1150 truck. Can't say that's worth it.

I am SO getting the premium membership here soon as I can - y'all are lifesavers!

 

[shucker1]

Why do you think we are here?

Don't underestimate your skills.

Takes time to learn this stuff.

You can do it.

Just be careful.