22mr2

Its a 93 22re 2wd 5spd. Im having a problem only while driving where it has no throttle response from 1/2 to 3/4 throttle. Once it gets past 3/4 throttle it comes to life. The problem can last for 5 minutes, than go away for weeks. Rain does seem to enhance the problem, but it has also happened on totally dry days. Pushing down the pedal does nothing, no miss, no ping, only the surge when it hits wide open throttle. No check engine light. I have replaced the tps and afm off another vehicle and it does the same thing. Changed the cap,rotor and wires. Sealed off everything with ignition sealer. No difference. No pieces of cat floating around in exhaust stream, egr isnt sticking and every ground I could find I cleaned. Any suggestions?

894x4pickup

Check your timing maybe???

rngrchad

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iamsuperbleeder

this sounds... disturbingly familar...

have you tryed searching perhaps?

abecedarian

umm... ground wires?
:shrug:

22mr2

yeah, valve timing and ignition timing are correct and I did the "pain from that chain" overhaul a few thousand miles ago. I did a whole lot of searching and found alot of people who have very similar problems and none of them have found a solution or never posted where the gremlin was. I thought it may have been the speed sensor, took one off a junk w56 but it was in rough shape. I took the old one apart and cleaned it up hoping it may have been some corrosion that was letting moisture seep in thru the o ring. Ok so far, crossing fingers!!

iamsuperbleeder

Just fer kicks, search "black goo", you might find my old thread I made when I was having the exact same problem...

pop the hood and see if you have similar symptoms in the TB...

22mr2

no black goo, recently when I did the timing chain, I had pulled the engine out and did a very good cleaning of the throttle body and the upper and lower intake. Also had lapped the valves and new stem seals and had the head cut. The truck did have this problem previous to all the work I had done, I was hoping it would have been taken care of but gremlins know how to hide!!!

Georgiadave

It might be a vaccum leak. Have you replaced all of the hoses?

Is the fuel pressure in the normal range?

Has the filter been replaced? The problem reads like a clogged fuel filter is the cause.

eatmorechicken

Just a shot in the dark, but might wanna check for leaky injectors. Just a thought since you've tried everything else. If their leaking it would be too rich to run right at low rpms but soon as you got on it, it would lean out.

Bill54880

I was having a similar problem with my 1991 22re and it went away with a new O2 sensor and I didn't have a code either. Just a shot in the dark that paid off.

22mr2

Still working on the problem The fuel filter was replaced when I had the intake off and I didnt see it really being in the fuel system because it was intermittent. I had thought it may have been the vacuum switch for the fuel pressure regulator and had run it on direct manifold vacuum and it didnt change it.
I had noticed that it had a water leak by the ecm and thought maybe that moisture was getting into the ecm. Took it out, took off the covers and the ecm is clean and bone dry.
Since I got it to happen for a few days, I can give a better description of the problem. The truck starts right up, every time when it is cold. Runs fine right up untill the temp guage is in the switching from open to closed loop range. As soon as it hits this point, thats when it starts acting up. Off idle cruising is fine. Its when the throttle is in the 1/4 to 3/4 throttle range where there is 0 change in engine power. Push it past 3/4 throttle and its fine. There is no miss, no stumble, the only change is in the soundd of the air going into the throttle body. Whats odd is if you hold the pedal dead still in one of the dead spots and wait 6 seconds, it kicks in as well.
It also only happens shortly after a decent rainstorm and will do it for about 4 days after. A week without rain and truck runs great.
I had thought o2 as well, because of the timeframe where it starts acting up, once it starts going into closed loop and the computer now looks at o2 readings. Changed that as well.
Also relooked into the egr(this has no egr temp sensor) and tried running it with the vacuum hose pinched off, no change. Tried yet another afm and no change.
Thought I had it pinned on the vss, had read a tech article in motor magazine about a frequency issue in the sensor output that was just like my problem but another sensor didnt fix the problem.
Also had thought it may have been a moisture issue in the coil or the ignitor and swapped 1 off my other truck, with the cap and wires. Nope, not that either.
There is no vacuum leak, except for the ones I keep making when disconnecting stuff! I havent checked the fuel pressure, only because there is not a total loss of power, just in a specific area of the throttle. Although I tried another tps which passes all of the resistance checks, im starting to think that I have a wiring issue somewhere in that circuit.
Waiting for rain again!!!

22mr2

Not in the tps circuit, same exact problem with tps disconnected. Has anyone run into wiring issues in the harness with broken wires? Around where the harness bends around the intake plenum or where the afm/coil igniter leads branch out?

22mr2

finally killed the gremlin!!! Found a splice in the o2 sensor wires by the transmission. The wires were soldered and shrink wrapped, taped up and buried back in some loom. One of the solder joints had a sharp point in it that was poking into another wire. Re spliced the wires, put in a new o2 sensor and the truck runs great!!!!!