I have a 96 Chevy G10 / Express 1500 van with a 5.0 and approximately 145,xxx miles on it.
I have been struggling with issues relating to this van for probably over a month now. The van had some driveability problems - rough idle, surging, lack of power, etc. One day, the van died on me/stalled several times. Shortly, after, per the suggestion of a mechanic, I had the PCM replaced. For a while, the van did not die on me, but still exhibited driveability problems. Per the suggestion of shop and mechanic, I then replaced the catalytic converter (just yesterday actually).
Today, as I was going into the turning lane, the van surged/"bucked" (best way I know how to describe it), the "Anti-Lock", and, I believe the "Brake", light both flashed on. The speedometer fluttered. As I was actually turning, it did something similar (I was primarily watching the road rather than the gauges). Then, a little bit later, while I was getting ready to pull out of a parking lot, the van died on me. It did not start again initially. The "Check Gages" and "Battery" light were on; however, the radio and clock actually still worked. I was able to get it started again after a few minutes or so.
Additionally, the van still exhibits many of the earlier driveability symptoms. Specifically, it idles rough and lacks power. At idle, a "tapping" noise can be heard; it seems louder once the the van warms up. The tapping noise appears to be coming from underneath the vehicle, within the front-third area the van. A low whining or whirring noise can be heard occasionally at low speeds and idle. There are currently no check engine lights on.
Initially, I had suspected a vacuum leak (based on the power "surging") and rough idle. However, I though the tapping might be more indicative of an exhaust leak. I could not locate any exhaust leaks, but I suspect it might be around the manifold. I had also thought a faulty EGR valve could be the cause. However, I am not if any of these would explain the stalling or odd behavior of the dash lights and gauges. While driving, the gauge that measures the battery's charge/volts never indicate any reading that I would consider abnormal, and I do not believe the battery has ever come on (until the van died on me).
A few specific questions:
- If the van stalled because of a problem with the alternator or
battery, would the radio and clock continue to work?
- Is there any easy for the average individual to locate an exhaust
leak that is closer to the engine, or would that be a job best left for a mechanic?
- Might be a dumb question, but is it possible for any mechanical failure of a sensor (or other like failure) to "confuse" the computer so completely as to cause the gauge and dash light issues noted earlier?
Recent work: new fuel and air filters, spark plugs, wires, and distributor cap, PCV valve, replaced intake manifold gaskets, catalytic converter, cleaned MAF sensor, and replaced PCM.
Thanks much for reading (sorry for the length); I would appreciate any suggestions.