Hails from Grass Valley, CA!

I joined this forum because I am in search of help. I am a full time auto mechanic for a local shop and I just started having driveability issues about three weeks ago with my own vehicle. I'm stumped guys. I've thrown the book at it, my wallet, hit it with my purse even and to no avail.

I've read a bunch of pages of threads already but have found nothing helpful. I'm gonna go post a thread about my issues meow.

 

Welcome to the forum, are you going to keep us in suspense?

 

Ok so three weeks ago my runner (1994 with 270k developed a hard starting issue. Added injector cleaner to a full tank and it went away. Less than a week later a different problem started emerging. Random, barely noticeable hiccups at highway speed. Barely even saw the tach needle flicker. A couple of days of this and suddenly I had no power.
I get 1/4 throttle or around 3k rpms before it falls flat on it's face. I can coax it up to 4K playing with that 1/4 throttle but not over.
Sever boggling on any incline. Hills I'm used to easily keeping the 55mph speed up I've got my hazards on and am struggling to do 25mph.

I've done a lot to it in an attemp to figure out what's going on but it keeps getting worse.

Here's what I've done.
-Checked codes found none
-Ohmd old aftermarket TPS, couldn't get it right so I replaced it with factory. Adjusted it and double checked adjustment.
-Checked timing and set at 10° btdc.
-Checked both fuel relays in the cab for continuity and they both check out, I even swapped them once to see if it made a difference and it did not.
-Ohmd the VAFM, even used a temp probe for the last test and it check out as good.
-Cleaned the temp sensor in the VAFM wit MAF cleaner.
-Applied vacuum to the EGR and physically saw it open.
-Removed EGR and checked to make sure it's closing all the way and it is.
-Made sure it was actually getting vacuum from the TB and it is.
-Replaced the upstream o2 sensor
-Coolant is full and clean. Smells like coolant.
-Ohmd the 3 injectors on the driver's side. All read 14.2 ohms.
-Replaced the fan clutch
-Replaced the fuel filter
-Adjusted dashpot
-Checked PCV, found it functional
-Inspected all vacuum lines for cracks or damage and found everything in order
-Sprayed carb cleaner around manifold and plenum looking for vacuum leaks and found none.
-Found the wiring harness for the knock sensor pigtail had a pin inside the connector that was pushed out the back of the connector. I fixed that thinking that was for sure it but nope.

It's acting like the cat is plugged but there is no cat.

 

Last week the bogging got really bad so on a whim I sprayed off the temp sensor nub in the Vafm and it clears up.in fact I drove about 500 miles over that weekend before it started stumbling on me and not revving up again. Interestingly, spraying it again did not have the same effect.

 

Last night I pulled the Vafm off completely and felt a sort of sticky spot about 1/4 of the way through the first bit of travel of the flappy door so I completely disassembled the Vafm, cleaned, and (very lightly) lubricated the bearings the flappy door shaft rides on and the sticky spot went away. I reassembled it exactly as it was before because I was careful with marking things and taking videos of how it was before hand. After reassembly I ohm tested it according to the Haynes manual and it is still within spec.

 

Anyway, this is my daily driver I cant figure out and I'm an auto mechanic
Would my gauge still work if my ECT sensor was.on the fritz?
I guess I'm down to replacing the fuel pressure regulator, fuel damper, fuel pump, vsv, downstream O2 sensor, checking compression, I spose I could also pressure test the radiator and do a leak down test and if I still come up short, I guess it's a tear down, at least to the injectors where I can ohm the other 3 out, individually test them and replace their o-rings. I'm just hoping someone else has been through all this trouble before and reads my thread and goes "AH HA! That happened to me, here's what I did."

 

Welcome and best of luck tracking that issue down!