Jerky throttle :(

[Geoff]

My '92 seems to have an issue with the throttle being either unresponsive or jerky, especially when cold.

All brand new:
NGK Spark Plugs
TPS Sensor properly calibrated using Select Monitor at the dealership
2 new O2 sensors
Air Filter
Fuel Filter

Have tried:
2 Different MAF sensors, same results

Basically, I keep my foot at the same place on the throttle, and after a moment, the car jumps up and goes. If I give it more throttle than about 20-30%, it doesn't do this, but it does get annoying. It's almost like there's some sort of lag going on.

Any ideas?

[icingdeath88]

Maybe the TPS is just bad?

[Geoff]

Originally Posted by icingdeath88

Maybe the TPS is just bad?

Nope - Have tried 2 used and 1 new TPS. The TPS registers correctly.

[Cam]

You can test your crank/cam sensor. Alldata says to test for a wave signal using a magnet. In other words, take a volt meter and connect pos to one of the prongs and neg to the other. Wave a magnet in front of the sensor and see if it registers a change. I don't know what the values should be exactly, but if they are all three the same ballpark, I doubt that they are bad.

[michael]

Have you checked for codes?

[Geoff]

There are no codes. Engine idles a little rough in Park as well.

[1986nate]

Check the coolant temp sensor if you haven't. Only about $25 for a new one. Often times won't throw codes when they're going bad, ESPECIALLY on 92's.

[Cam]

You can check the cts with an ohm-meter. It should read 2k-3k ohms when at room temp. Roughly 60 degrees. When warm (about 170 degrees) it should drop to 400-600 ohms.

[Geoff]

Where's the Coolant Temperature Sensor located? Any pics? I've got a multimeter I can check it out with.

[1986nate]

It's on the coolant crossover pipe, on the driver side of the engine. Take off the H6 engine cover and there are 2 sensors just below the intake manifold. The one with 2 wires and larger connector is the one to check.

[Geoff]

Just replaced the sensor - It was only $22 shipped, and I'm sure it's never been changed. Since the drivability issue was intermittent, will have to see if the new sensor helps...will post if it does.

[Geoff]

Nope, new coolant temp sensor didn't fix it. It's usually from a start or low speeds...nothing, nothing, then SURGE of power. Should I look into doing the crush mod? Any other ideas?

[Geoff]

Tried in manual as well....the throttle hesitation is still there in first from a stop. Any ideas?

[Geoff]

Just ordered a NEW MAF. Both of the MAFs I'm using are original. Even though I've cleaned them and received similar results, won't hurt to try, since I've replaced both O2s, all of the injectors with rebuilt ones, the TPS (adjusted as well) and plugs. Running out of things to change now. :P

Engine seems to idle smoothly while in gear, not in park or neutral, and throttle response is still uneven, SOMETIMES. :P

[michael]

I. Wish I could remember but I had the same symptoms that a sensor fixed. I thought it was either a knock or o2. If you did the o2 already you may want to test your knock sensors.