I have a 91 hatch with a 97 ls running obd1. In cold mornings, it has a rough start but gets normal once warm. Major problem i'm having is, once in a while when im braking to stop...car either drops idle to 200-400 or shuts off. Starts right back up but once it starts, it keeps going. Any ideas?


I've changed the PCV valve, cleaned the IACV, and adjusted the idle.

 

Maybe electrical?
I know my car did that a few times before my alternator/battery **** on me.
I might be wrong, but it might be worth checking out.

 

Battery is brand new, altenator does look old and I haven't changed it since the 3 months i've had the car. Maybe?

 

check your map sensor

 

how?

 

try replacing it with a known good map sensor, is yours on the firewall or throttle body

 

yea bro my 90 crx b18 a1 swap does that to and i cant figure out what ut is.......some ppl been telling me to check the tps and some been telling me to check the coil but in all i think i am gonna check te fuel filter too whie i am at i.

 

My map sensor is good, I got it on the TB. My dist. is brand new and so is my fuel filter. My gauge reads 40psi at idle.

 

you can check your map sensor by unplugging the vacuum hose and see if there is a difference, or try putting the map sensor vacuum hose to a different nipple on the TB. or bring the alt to advanced or something the will check it most likely for free