No Check Engine, no codes running but rich and rough

95 taco with 3rz 2.7 4x4 manual 270k + miles
filled with gas yesterday for out of town drive
50 miles later running rough, no visible smoke ,heavy miss on acceleration but maintains at 55-60 in 4th and 5th
made the round trip with much discomfort
change of plugs and wires noticed all cylinders black carbon powder coated tell me rich on fuel
no check engine light but hooked up OBDII scanner and get error restart scanner and it runs for 5 seconds and shows 0 dtc
tested scanner on 01 tundra and get expected results of codes I know about
started the truck back up and disconnected MAS for about 15 seconds. still no light and still no codes picking up on scanner.
this scanner has worked in the past on my truck so i am ruling the scanner itself out.
would the truck even run if the system was out or is there something else i should be looking for? I did check the underhood OBD and efi fuses

 

What's your LTFT's?

 

whats ltft

 

Long term fuel trim.

 

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3020rs scanner and limited knowledge with small budget

 

So, CEL is back on. not sure why as did nothing but plug a couple different scanners in. mine alternates between error and no DTC's, the other 2 just say no connection.
but at least the light comes on dim in on and bright when running.

 

Try cleaning the MAF. Use MAF specific cleaner and spray up in the little tube too. I used a q-tip soaked in cleaner to clean the bulb a little more.

Also there should be another OBD port on the intake manifold on drivers side, see if that one works. My under dash one is finicky.

 

If the fuel pressure regulator has a vacuum line on it. Pull line off and check for gas in the line.

 

fuel pressure regulator vacuum line is dry.
This is a brand new plug with under 100 miles on it.
when ignition is on but not cranked I hear what I thought was a fan but it is the EGR vsv under the plenium. should I be hearing this and could it be sending a signal for more fuel?
Check engine light is on full time now but keep getting either an error or no DTC after 3 seconds of repressing link button on scanner.

 

Injectors dirty or clogged causing a poor spray pattern.

That will not trip a code .

 

not sure I mentioned, plugs are like that in ALL 4 cylinders.

 

try pimching off or plugging the line from the evap purg vacuum switch.

 

here is where I am at now
added seafoam to tank and filled half way (7 gallons gone in 110 miles)
Changed air filter cleaned the new plugs and cleaned MAF
tried both pinching of and individually disconnecting all lines on egr with no variation in idle
sealed up air intake pipe leaks and changed out vacuum lines that looked suspicious
even went ahead and changed upstream 02. What a nightmare as stud broke off in pipe and now is held in with pipe clamp
cleaned inside distributor cap (does that rotor pull off? tried but would not just pull out)
still hard miss at higher RMPs, weak on hard acceleration
pulled OBD and EFI fuses for 10 minutes followed by disconnected battery to try and reset the CIL
things noticed in process.
idle seems a little high not smooth
hairline crack in exhaust manifold between 2 and 3
long term oil leak on exhaust side either front cover, oil sending unit or both ( leaks about a quart every 500 miles)
permanent CLI but scanner gives no dtc and I have tried 2 different Innova brand scan tools)
Still running extremely rich which sucks cause I have to drive 10 miles to work each day as no back-up)
next course of action I am checking downstream 02 once I figure the procedure out

 

Did you pinch of the EVAP emissions vac line to manifold? Also a an EGR valve that's not seating will cause a running rich problem. You'll have to remove EGR valve to check that.

 

Have AutoZone scan it for codes.

 

Yes per the above diagram I pinched the line with no change in idle. If I disconnect, idle drops.
Started to pull the EGR but ran into heart problems when I pulled whet I thought was a vacuum line and antifreeze started flowing. collected myself and followed that line to a point where both it and one of my heater hoses hook up, whew, not got to wait for another day when I can afford any extra hours.
and yes I have taken it to a couple different parts houses and they only get failures from the OBD.
started getting no starts and had to resort to spray starting fluid. Going to revisit the coolant temp switch I replaced a a year and half ago or so. that was the last issue I had with no starts.

 

Replace EGR valve?

 

Haven’t replaced but did apply vacume and motor stalled

 

I also pulled the egr valve and cleaned it up .