Ok I have a 93 Toyota pickup. 22re 4wd 5spd.
With tps plugged in I have a miss at idle but it's very random. when the motor warms up it try's to die. And if I give it any throttle it chokes itself. Can't drive down the street

When tps is unplugged idle jumps up a bit. Random misfire still there. And it allows me to some what give it throttle. Its the only way I can drive down the street and I cant do over I'd say half throttle give or take or it stumbles.

I ohmd the tps and everything is in parameters. I did reset it just to do it and still the same. One thing I did notice is while slowly opening it the reading jumped around.

Could use some how cause its starting to get annoying. Things already replaced : afm with used but known working afm, distributor cap, plugs, wires, coil, fuel filter.

I'm trying to tackle one problem at a time and this is the main. Only other thing that comes to real notice is a pretty bad exhaust leak on the down pipe.

Any help is greatly appreciated. And yes I've read plenty of other threads. Mainly trying to figure out the misfire. Can it be cause by the tps?

 

Timing? You have to have the tool http://www.harborfreight.com/xenon-t...ight-3343.html, but otherwise you're just guessing. The TPS does affect timing, but unless it's set correctly in the first place you'll never know what else is involved. If anything.

An exhaust leak can eventually throw a code (excess oxygen sucked into exhaust stream confuses the O2 sensor). Not to mention it can kill you.

 

From what I've ready I can't properly set timing if the tps is off right? Or am I misunderstanding that? Thanks for the reply

 

Well, that's what it says. The only TPS signal of importance at idle is IDL. http://www.ncttora.com/fsm/1990-1995...e/throttle.pdf The jumpering called for in the timing setting procedure bypasses that signal, and is supposed to change the idle speed slightly. It doesn't do that on mine or several other's on this list (with correctly set TPS).

The bottom line is that, at idle, the TPS has a small effect. So if you're trying to set it to 10 degrees you might end up actually at 12 degrees. But at present you don't know if you are even in the right neighborhood! Who knows, once you set the timing correctly, it may turn out that your TPS is fine.

Last, checking the timing is a) easy, and b) something you have to do at some point. (Not the same for the TPS.) If the reason you're not doing it is because you don't have the tool yet, now is the time to pick one up.

 

K I'll give it a try tomorrow. I have a timing light but it's in my storage. Thanks for the input so far.

 

The IDL signal from the TPS MUST work properly else the jumper in the diag check connector won't set the ECU in to the proper mode for adjusting timing. You can adjust the timing, it just won't be right. You may be able to get around that if you insert the jumper in the check connector, then loosen the TPS just enough so you can move it in very small increments with light taps on the housing. You should bump the top towards the radiator until you hear the idle speed change, bump it the other way until you hear the idle raise, then bump it carefully back towards the radiator until the idle drops. Then you should be able to adjust your timing and idle speeds. If you replace the TPS, you should go through and adjust it and the idle/timing again.

But, you said,
That sounds like a vacuum leak to me (cracks in the boots to the tube, PCV maybe)... or maybe a sticky AFM vane.

 

Ok did ignition timing. Jumpered it and set to 5. Still didn't do any better. Noticed that the ignition timing was kind of jumpy Unplugged the tps. Rpms went up and I noticed the ignition timing went off the chart.

For sh**s and giggles I undid the vacuum line to the fuel pressure regulator and got no change. Does this mean I have a vacuum leak? I've sprayed several cans of throttle body cleaner with no luck on a change.

Another thing I did was unplug the hose to that canister looking piece under the throttle body that the small hose on the intake runs to and had no change.

Any help is so appreciated right now. It's my only vehicle. Yes I can run back and forth to work but I'm nervous of causing further damage. Thanks guys

 

Ok picked up a throttle body off a friend with a known working tps. Going to try that ptomorrow. And I'm also going to recheck all the vacuum lines on the truck.