My 1990 Honda Prelude SI stalls when driving at about 1500 to 2000 RPM and sometimes at freeway (55 MPH) steady speeds. I have replaced all plug wires, coil wires, new plugs, new coil. I have checked the ignition switch trying to get it to stall at idle and it wont stall at idle at all. The vehicle never dies and the problem is intermittent. It's like someone just unplugs the engine for a second and plugs it back in and everything stays running. The vehicle has not died yet. This has a automatic transmission as well FYI. Vehicle starts everytime and never dies at idle.

 

likely going to be main relay or distributor(ignitor or coil)

 

Thanks, I have replaced the coil. The car runs fantastic other than the occasional stall. The car never shuts off or completely dies. Hard to diagnose because of it being intermittent. I will try main relay. Distributor if I have to.

 

if you want to test for fuel you can get a harbor freight fuel pressure tester and hook it up and just drive around with the gauge under the hood facing you in the windshield and when it stalls see if the gauge is dropping to 0

but it's really good maintenance to replace the main relay anyhow, as well as for the distributor if the bearing is starting to fail which is characterized with the red dust of death developing inside it

 

Thanks for all the help. I will post when I get it figured out.

 

Any stored trouble codes?
the b21 is obd1 and is usually pretty good at picking up on issues and throwing a code
could also be a bad ground somewhere. clean and tighten the harness ground on the thermostat housing. And clean and tighten all other grounds that you can find

 

try to clean injectors also

 

Thanks for the ideas I will get them done asap. It did throw out a code for TPS and I have had it replaced and recalibrated and it fixed the other problem which was limp mode and poor running. All was good for a short while then it started doing this. I have a friend that helps me with my wrenching. I am the help from the neck down. lol so I will share these threads with him. Thanks again guys.