Constantly blinking CEL when reading codes
 

Hi all,
Bought a 95 4x4 had a code 25 and rough idle , low power under 3000rpm.....new ECT,O2S and located a few intake leaks. Also replaced distributor that was squealing loudly. Idle better but rough, still sluggish under 3000rpm and fails smog miserably- +2000ppm HC. Yes over 2k .......smokes a bit too.
No CELL flashing but with jumper in place CEL flashes constantly. I have read codes before and I'm positive there are no breaks or pauses just a steady blink. Plugs still read lean and o2 sensor was a little white as well when changed. I'm thinking lean misfire resulting in unburned fuel at tailpipe.....whats up with the steady blinking CEL when diagnosis jumped?
I tried searching and could only find info on blinking CEL when NOT jumped. Mine is only when trying to pull codes. Maybe ECM is bad? Anyone have info for me or a direction to get it?
Manual transmission

It means you have no codes.

Wonderful......a code would sure help.
Just pulled plugs again and 5 look good to slightly lean and #2 cylinder carbon fouled.....not wet just dry carbon. Only one cylinder and it's dry carbon fouled......lends itself to a bad injector, yes? Spark issue would be all or more than 1 cylinder......bad rings would usually have a wet or oiled plug and since it just rips above 3k rpm kinda says valves are in decent shape, yes?
I'll swap out the plug wire on that cylinder just in case and change the injector too. While I'm at it, yes, I'll check the TB coolant lines and TPS calibration. Hmmmm as I talk this through i should have checked the TPS already.......
I'm learning, any input is appreciated!
WOT above 3k rpm is killer........

Is a bad spray pattern enough to effect the impedance of injector when checked?
Or more succinctly,
Can an injector test good impedance and still have bad spray pattern?

An injector can surely be bad even when it tests electricly good.

Thanks. I have extra injectors, I'll just change it.

Update
#2 compression is 0. Yes, zero. A little 30wt in the cylinder and no change. Hmmmm, check #4 and it's 165 so my gauge is good. Must be a valve....but zero compression? Would have to be stuck open or more likely bent in open position. Lifter is very loud from that area. And how does it running so well above 3k rpm figure in. There is some intermittent issues as well, meaning sometimes it runs well sometimes it doesn't. I guess it's plausible that a stuck valve or bad guide is causing intermittent issues and I ran test with it stuck open bit that's a huge reach.......
So, this is what I'm doing......
Seafoam, in the oil, in the gas and did the vacuum add about 6 times. I'm going to continue running Seafoam for up to 2 weeks and I'll do several bottles through the intake vac during. I don't really have much hope this will work but I figured it was worth a try.
Still no codes. Is the blinking CEL a no code signal 100% certain? I can't find anything that states that except word of mouth.
I'll let ya know what happens.

If anyone has any other ideas or thoughts please contribute.

100% certain. Don't believe me? Let me quote the Factory Service Manual for you.

I couldn't find it. Was more perplexed as to how in could be running on 5 cylinders and no codes. Thank you for the info and the follow up.

Blinking CEL
 

1.) A blinking CEL at regular intervals indicates that no code is set in the memory.
2.) Zero lbs. compression in a cylinder indicates that there is something mechanically wrong.
3.) You can throw mega gallons of that Seafoam crap at it for years, and it ain't gonna fix ZERO compression in a cylinder. Duh!!
4.) Bite the bullet, and remove off the head, BOTH if is a V6, chances are that you bought a dud when you purchased the vehicle.
Not trying to be mean here but be real.
It is what it is.

Agree with everything you say, however a motor on 5 cylinders doesn't get 19mpg and rip uphill above 3000rpm. Intermittent issues and great performance above an rpm range don't indicate an immediate tear down to me. I don't expect seafoam to do miracles but I also can't explain what's going on.
Today I started the motor and checked cimpression while running. It was erratic.....45psi then 90 then 120 then I released pressure and it did same thing.
Thanks for the input tho.

Could be a sticking valve, but more likely a burned one. As such it has a big enough hole to completely depressurize the cylinder at low speeds, but at high rpm's the hole is too small to let all of the gases escape so the cylinder pressurizes and fires and provides some power.

The head needs to come off. Even if it's a sticking valve, I've never had a case where one could lubricate/clean it back into proper operation.

If it's just a valve, you can probably get away with just pulling the head for side with the offending cylinder, and leaving the other side alone. Not ideal, but better than nothing if you're trying to save short-term time and money.

Thanks......reached a similar place yesterday. It's fatal......I have another set of heads going to machine shop tomorrow. I'm half tempted to drop 2k on one of those ebay engine builders for a new long block instead. I considered the swap but I can do a full rebuild with 200 hp and custom exhaust with headers for half the cost. I've had several 2nd gens over the years and the exhaust is the real weak link IMO.
Thanks for chiming in......