Running Sluggish

[shaneland]

We have a 93 Olds Silhouette with the 3.1.

What happens when we drive it is:

When I jump on the gas in park it accelerates throughout the RPM range with no problems. However if I gently step on the gas up to around 1500 rpm's the vehicle carries on and misses and rpm's drop.

While driving and pulling out normally the van seems to surge and buck from idle to 2500 rpm. After that the rpms are to high to notice any missing...

I have replaced the wires, cap, rotor, plugs and O2 sensor.

I also got check engine light code 42. Which is Electric Spark Timing. The book says the bypass circuit is open or grounded. A malfunctioning HEI module can cause this code.

There are a few things I am writing about in this thread...


1. Is there a way to find the exact problem or should I just replace the module and pickup???

2. What is the correct way to set the timing? The book says to disconnect this tan wire (which disables the EST) that runs along the pass. side near the shock tower. I dont have a wire there that is by itself.

3. What else is there??? What could be the problem? Could it be something with the fuel I overlooked??

The injectors have a good spray pattern so I dont think its that. I did NOT check the fuel pressure. Could it be the throttle position sensor, crankshaft position sensor,speed sensor,spark knock sensor???

[richtazz]

it's either the module and/or pickup coil like you mentioned, or low fuel pressure. You can remove the module and have it tested at Auto-zone or Advance. Just make sure they run the test enough times to get the module warm to the touch in case its breaking down after it heats up. you can test the pick-up coil with an ohm meter. correct resistance is 500-1500 ohms, anything higher or lower means its bad. Make sure you wiggle the wires while testing,one of the wires could have a break inside the insulation and wiggling the wires will cause the reading to jump around if this is the case. You must find that tan wire to set base timing, otherwise the ecm will keep adjusting against you, and you'll never get it right.