94svt50

My truck is an 1989 4x4 22re. Im running out of ideas on what could be causing this problem. Okay, here is my problem. When the truck has been sitting for a while after having been driven a good distance, long enough to heat things up. When you start it back up it runs and idles realy rough, but it starts up just fine. Then when you push on the gas it just hesitates and bogs down unless you push it to the floor then it takes off like it should. But, when you back off the pedal from the full down position it starts bogging again. It will do this for maybe a 1/10 of a mile then it runs like normal. Or you can just let it sit and rev it a bit for about a minute and then it runs fine. It never does this when the car has been sitting long enough for every thing to cool down, like a couple hrs. Or in the morning when the truck has set all night. And it always starts right up initialy no matter if its hot or cold. Some things I have checked already. Coolant temp sensor: in range, TPS in range Mass air sensor is suspect though Its a couple hundred ohms out on e2-Vs pins and Im getting no continuity at all on the E2-THA pins, they are the air temp sensor portion of the mass air unit. The question is if this part is bad wouldnt the problem be there all the time and not go away after a minute? I checked the parts hot and cold not much variation. Another part of interest is the signal generator pickup, in the coil its a little bit out of range on the ohms when hot, but not when cold. But also, if it goes bad hot why not when driving down the road hot? Whatever the problem is, it is related to heat while sitting not running. Because the heat of stop and go driving does not cause problem untill turned off and left to sit. This problem started last summer, but went away in the fall and is now back. Any ideas suggestions would be greatly appreciated.
Thanks. jon

yotakid661

accelerator pump maybe?

94svt50

Not sure what that is? different from fuel pump? I thought maybe the fuel pump was heating up and when enough cold gas ran through it, cooling it off. But, the fuel pump is an electric one in the gas tank, so it should be isolated from heat.

randito

Maybe a sticking EGR valve?

94svt50

Possible. Wonder how I could check that?

yotakid661

is it carborated or fuel injected?

94svt50

Its fuel injected.

yotakid661

lol then i was wrong. Sorry dude

94svt50

Followed shop manuel and tested EGR, its functioning normal. This really has me beat.

Kiroshu

Tune-up sir?
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95 Toyota 4runner SR5 V6 3.0 Automatic 149,850 miles

94svt50

Plugs, wires, cap and button and 02 sensor have about 20k miles on them. Coil and fuel filter have about 75k on them.

toytech76

of course check all your tune up items. When were your valves last adjusted? If your AFM is reading out of spec, I would be very suspect of that

94svt50

Yes, it has me concerned. Only drawback is the ohms are out of range both when the problem is ocurring and when the truck is running fine. Only a slight ohm change with temp. Unless, this out of range only effects a short period upon initial startup when warm. I just need to make the connection before I spend the big bucks for this part. Now, the pickup coil in the dist. reads out of range when hot and in range when cold. But, it can read out when the truck is running fine after that first initial minute of running. So, I just dont know.
thanks

toytech76

doesnt sound like a spark issue to me. I would see if anyone near you has a AFM you can try out and see if that works

stupid_mud_gremlins

could the cold start injector be stuck on, anyone know if this would cause the problem?

rowdy235

I don't know why but for some reason I'm thinking fuel filter. In my experience, when the filter is clogged, it causes the engine to bog down, like yours is doing sometimes. I would start by replacing that.

94svt50

I checked the ohms on the cold start injector time switch and it was within range. This problem is extremly consistent which is a bit nice in a way, can test things during and after problem goes away for comparison.
thanks for the replys-jon

94svt50

I changed it about 50k miles ago. When it went bad before, the truck would just die and you could let it sit for a bit, fire it up and it would run for a minute and die. I guess after a minute enough gas would soak through the clogged filter to start. When it used this small amount up it would die again. No more backwood stores with ancient gas pumps full of rust for me.
thanks for the replys

94svt50

What about vapor lock in the fuel filter?

mudtoy1986

well i had the same prob but mine was worse change youre coil if u have a bad throtle senser ure truck will idle up and dow speraticaly if u have a bad idle air control ure truck will idle badly when ure at a stop light so try the coil and maybe ure fuel filter