So my 97 LS went through a crazy phase of misfires, over heating, and power loss. I changed the water pump and timing belt (unrelated but figured do it since I am replacing the water pump), spark plugs and boots, distribution cap and rotors. She drove smooth for few days but now she's misfiring, only when I'm idling at operating temperature. When the car is below operating temp, you can barely tell its running. Once I reach operating temperature the car drives smooth and no misfires while I'm driving and accelerating or decelerating. As soon as I come to a full stop it's like I'm on a camel. What could cause this?

 

Coolant temp sensor?

 

Any error codes?

 

I replaced it less than a year ago, i doubt it has gone out.

 

Those area the errors I'm getting. Its weird though because my car shifts like a charm and I already replaced my 02 sensors less than 6 months ago

 

On a side note. Any tutorials for 97 ls4 head gaskets? cant seem to find it.

 

Check the ecu caps, need to see real time O2 voltage and fuel trims, possibly just replace o2 sensors. Need to make sure the wiring is okay too. You need some one with a good scan tool.

 

already checked the ECU caps and all looks good. replaced them about 2 years ago. and already replaced the o2 sensors less than 6 months ago.

 

Then instead of more hit and miss, and guess work, find the person with the good scan tool, like a snap on verus or modis to check it out.
With an OBD2 car it is stupid not to do this.
Also you can get a fairly good scan tool from Harbor freight now Maxi das or what ever its called and about $1000. but it won't do OBD1 and that's why I've shyed away.

 

An update to whom it may concern:

After all the crazy missfires my car ended up overheating bad, like 50ft and overheat bad. I changed out the thermostat again, the water outlet was cracked and replace, water outlet gasket was in bits, had to flush system, lower radiator hose started to collapse so I changed that, a hose near the top of the engine was leaking from end so I got a new hose and clamp, then the upper radiator hose did the same thing. After all that was replaced and went through gallons of coolant, my exhaust started shooting white smoke. Looked into head gasket but found a blue devil (#1 fan) head gasket sealer. Used it and white smoke was gone and car stopped over heating in place. Took it for a spins in my complex and all was good, went out on the street and not even third of a mile and temp started to rise. I wiped around and parked in my complex and out of sheer frustration I popped my hood and started to cus my engine out. Heard a hissing but couldnt see where it was coming from, so I went around and leaned over my res tank to take a look at my hoses and near the radiator, and too my surprise I practically burned my chest. Turns out the res tank cap i bought from auto zone while back was rated for only 9lbs of pressure while my LS needs 13lbs. I bought a cap from rockauto and my car has been working perfect, drove 200 miles in last few days and needle hasnt moved a milimeter. The camel back misfires are gone too. The engine does feel like there is a light surge when I idle though but its hardly noticable. I'll do research but anyone know what could cause the surges off the top of thier heads?