Need Advice On The Next Step

The car is a 2002 SL1, 1.9, out of warranty. Original problem was surging and loss of power, with SES light on. Replaced spark plugs which helped but continued to feel surging especially in 3rd gear under load. Replaced wires. Engine began to run at 1600 rpm. Has gone up to 1900-2100. Plugs, wires, and coil packs are new. Has had fuel injection service. Pulling code P0301 (cynlinder 1 misfire) and 2 consecutive P0507s (high idle, like I didn't know that). Assume that the misfire is triggering the high idle. But I also suspect that the ECTS is bad, which (although I don't understand why) I have heard can cause a misfire. But I can also easily understand why it would run fast if the coolant temp is being sensed cold.
Any advice on this or what the next step should be? And if it might be the ECTS, where is the little sucker? I worked in cooling systems for 11 years and though I could find a coolant temp sensor pretty easily but I'm damned if I can locate it.

Thanks for the great forum and for all your guys' great advice.

Tom

check over at saturnfans.com. the ECT is somewhere under the upper radiator hose and the EGR on the head(or at least it is on the DOHC, the SOHC can't be to different) also check the #1 spark plug to see if its covered in oil. and check the intake and EGR for carbon buildup.

check over at saturnfans.com. the ECT is somewhere under the upper radiator hose and the EGR on the head(or at least it is on the DOHC, the SOHC can't be to different) also check the #1 spark plug to see if its covered in oil. and check the intake and EGR for carbon buildup.

Thanks. The spark plugs are brand new and when I changed them there was no oil or residue in any cylinder.

Can the ECTS cause a misfire?

Thanks. The spark plugs are brand new and when I changed them there was no oil or residue in any cylinder.

Can the ECTS cause a misfire?

ECT = misfire? nope. ect mainly controls the fuel injectors and idle speed.

i would double check the spark plugs and boots, and head over to saturnfans.com, maybe they will know something i don't (which they usailly do)

ECT = misfire? nope. ect mainly controls the fuel injectors and idle speed.

i would double check the spark plugs and boots, and head over to saturnfans.com, maybe they will know something i don't (which they usailly do)

That's the thing, it's running way high. And I'd love to post at Saturnfans,com, but the administrator hasn't been able to get me priviliges yet.
It's running up about 2300 now. What about the TPS? There seem to be two sensors on the throttle body on the 2002. Which is which?

the one with three wires is the TPS, the one with two wires is the idle air control

I'm getting it fixed now. Turned out to be a vacuum leake in the intake manifold on #1. Mechanic said the gasket had gotten sucked in so bad at that point he couldn't even see it.

Thank you for your advice and thoughts! Hopefully this will help other dummies like me! :-)