My 95 sat sl1 has been acting up since the thermostat stuck closed, replaced thermo and coolant temp. Sensor. Coolant system then check out ok. Drove five miles to check running condition and fuel up. Tried to start after fueling, would turn over, but not fire the first three tries like it wasn't getting fuel. Since then ( three weeks ago ) I have been driving it only to and from work. The car runs great, but when idling it will stay at about 1100 RPM for while then jump up to 1400 back down to 800, then steady back out at 1100. It bounces like this a few more times then eventually stalls. After stalling will not fire until I let it set for a few hours. I have replaced the fuel filter, throttle position sensor, and idle air control valve. Checked all fuses/ relays and cleaned the EGR valve. Nothing helped. Could it be the fuel pressure regulator, fuel pump, or fuel level sending unit? Perhaps a vacuum leak? I don't know. Please help with any info or knowledge of the problem. The car is a 95, but the engine is a 99. In 2005, one of pistons broke so engine was replaced. Its been runnin' like a champ 'til now. Thank you for your help.
Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem
Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing
July, 3, 2011 AT 4:46 PM
I can hear the fuel pump come on, even when it's stalling.
July, 3, 2011 AT 4:49 PM
Check everything I've suggested-Try cleaning out the idle air control valve and see what happens
July, 3, 2011 AT 7:38 PM
Just to add to this one you said you changed the coolant temp sensor did you change the top one with one wire or the bottom one with two wires?Have you checked for trouble codes in the computer yet?That could even lead you to your problem.
July, 3, 2011 AT 10:42 PM
It was the top sensor, but do you know what the lower sensor is for? The only code I got was a 45 (running rich). I have changed the o2 sensor off the manifold about year and half ago.
July, 3, 2011 AT 10:44 PM
I still have not checked the pressure, don't have a tester.
July, 3, 2011 AT 11:08 PM
The IAC is new.
July, 4, 2011 AT 2:33 AM
You changed the wrong sensor the coolant temp sensor is the bottom sensor with two wires going to it. The top one is for the gauge try changing thr bottom one. Also inspect the connector going to it if the terminals are green or blue you will have to replace the connector also. That could be your problem a bad coolant temp sensor.