My 1998 Olds Silhouette van misses when carrying a load or going up a hill. It sets no codes. I have replaced plugs, wires, gas filter. Any suggestions?

Ignition control module is bad !

Most likely throttle position sensor is defective.

Do you have a fuel pump? If its bad or weak, you aren't getting enough gas to your engine. Has anyone thought of the filter in your gas tank?

If a crank or cam position is failing it will normally throw a traceable code. You could have a computer that is going bad.

First take EGR Valve off and clean it with a wire brush and a non-chlronated brake cleaner.If it still runs bad check your fuel pressure it should be 41-47 psi with key on engine off if not within specs replace fuel pump.

You may try a new air filter and perhaps have your intake cleaned. Now is it "jerking" on you? Perhaps at a stop light when the brake is applied. You may want to address the spark plug wires and plugs.

Could it be a coil? or mechanical wear on the valves or pistons?

2000 Olds Silhouette: plenty of gas in the tank but the gage will read full, 3/4 full, 1/2 full, and everywhere in between. Van runs fine. No other issues except the gage goes crazy and can't depend on what it says. ...

you can pull the fuses, but it is hard wired so it might have relays that need to be pulled, or you can just fix it, and replace the air shocks/struts with regular shocks/struts

Hi and welcome to FixYa,

Initially, check the wiring/connectors to the speed sensor. The speed sensor is at the transmission would look like the image below.

Incidentally, the speed sensor not only sends signal to the speedometer, is signals are also used by the engine computer and the transmission control. This would partly explain all the other concerns.

Check and perform preliminary visual or necessary inspection. Pls post back result(s). Good luck and Thank you for using FixYa.