97 se/na 3.8 stock. I had a problem with my PCV valve & repaired it. I check my mileage on the next tank & it was down to 24 MPG. I checked the plugs & they had a white/tan deposit on them. According to the manual it was due to burning off oil & additives. I replaced with NGK TR55 plugs. FYI-When I removed the #6 plug it was loose (removed by hand).When I started the car I thought I detected a miss so I revved it & it had a miss. The engine light came on. I checked the wires & I found a place on #6 wire that the plastic shield had melted. The wire looked OK but I taped it any way. I ran it again & the engine light went out but it seemed to have a miss at about 3K rpm. I took it for a drive & at first there was a miss but it got better. I went to Advance Auto to scan it and got a #6 misfire & 507-IAC. I revved it up slowly & it sounded like I was hitting a rev limiter at 4K. I drove it home running it pretty hard & it seemed to run OK. Engine light stayed off. Any ideas?

I wouldn't trust electrical tape to handle the voltages of a spark wire (~30,000 volts). If one wire is old enough to be worn out, you can't say for sure what the condition of the wire under the insulation is. Do yourself and your car a favor and get a new set. Also make sure your #6 wire isn't touching the nearby O2 sensor wire -- that could cause interference.

You indeed have a rev limiter at 4000 RPM, when going 15 MPH or less. To get around it, shift into neutral when you're moving, and it'll hit the redline limiter at ~6000 RPM. (Do this when safe -- don't kill yourself or others.)

Finally, 24 MPG on a 1997 SE? I only get that when I drive almost all highway miles. What'* your secret?

I get around 23-24 mpg as long as i dont race people lol but if you went DOWN to 24....^^^^x2 whats the secret lol

Well, after a week of driving like a grandmother, I got around 25 MPG (rough estimate) -- that'* the secret. I have a tendency to floor it. I guess we're both in the same boat there.

So how'* the car? Still acting up?

^^^hell yeah we are, there'* just those times....

The wires are new, one just got too close to exhaust. I checked the wire next to the O2. Thanks for the tip. Thanks for the info on the rev limiter. I didn't know it had one at 4K. As for the MPG--I did get 27 on cruise on long trips. Usually average 26MPG. The car seems to be running fine now. Leaving on a trip tomorrow. Pray it goes well.
Thanks again for the help. I'll post again after the trip.

Made it back! About 200 miles into the trip, I had to get on it hard to get around a truck. It had a brief hesitation and the SEL came on. I stopped at Advance & had a code for misfire-#6 cyl. Light was cleared and the car ran fine. It came on again on the return trip but went out after a couple of stops. I'm going to replace the wires even though they are new and check the coils again.

hahah glad to know you got back alright, i just took a 400 mile round trip visit to go see a friend and mine ran fine as well, not the same problem but i used to have a cracked fuel pump right when i got it, and the gas would leak and overheat my car...been a while since i got it fixed but its nice to know your car is reliable lol