missing and stumbling long

[RapidRide2]

I have an 87'gn with 113k on it. It has been tuned with turbolink by a qualified gn guy. The car has been super reliable. I rarely drive the car. However i had to take the car to get emissions tested the other day... I put a little prem in it and the catalytic convertor on and decided to sprint on the hwy to the test site. At about 80-90 mph the car fell on it's face. I limped it to the stn.. The car still passed. I got the car home had a friend hook up his turbolink and showed no codes,, ,he indicated that everything looked pretty good except o2 sensor mv's and the car did not show it going into closed loop on the turbolink???. I pulled the plugs and found #3 cyl. plug tip and electrode to be GONE!!!!!! The car was idling rough and seems to be idling very rich,according to the very strong fuel odor that isn't usually present,, fuel pressure is about 44-45 with line off. I replaced all the plugs only to find that the car is still idling rough and stumbling throughout the rpm range. I also took the cat convertor off with no success. I also unplugged the maf sensor and the car almost died. I'm no pro with these cars. If anyone could help with any advice it would be greatly appreciated.

 

[RapidRide2]

Anyone with any thoughts or ideas????

 

[ES1]

1st - Make sure wires are not crossed
2nd - Make sure you did not crack a plug putting it in
3rd - If you have an extra plug wire, replace the wires one at a time to see if that helps

Why happened to the plug? Detonation?
Make sure you have not blown a headgasket
Milkshake oil, bubbles in coolant bottle

 

[GNRick]

FP too high?

 

[RapidRide2]

I still can't figure why i destroyed a plug in #3 cyl??? tip and electrode-----GONE!!

 

[Robbie-87plz]

Could running lean under boost cause that?

 

[RapidRide2]

i have some update questions reguarding my problem,,,, I am thinking bad gas maybe?????? I checked the maf sensor,,, seems fine,,,, turbolink showed no codes,,, i pulled the valve cover to check that all the rockers were moving the same,,,ok on that. I put the valve cover back on. I decided to take the car out while it was stone cold coolant temp. It ran like a striped-ape and even so when it came up to 160 degrees??????? I have no idea???? The car was sitting for a while and i put only5-7$ of prem in it. I have a feeling that wasn't enough to bring up the octane of the old gas in the car. Then under full boost it leaned out #3 cyl. I changed to a new plug with the old gas however and it still and it still ran like crap???? after it was running good again for whatever reason i put more premium in it today and haven't had any problems so far,,,, really strange to me . Any opinions as to what it could have been????

 

[85HOT-T]

This may sound dumb but i would be wondering were the electrode is. You could mess up a valve seat or vavle. Worse the bore.

 

[RapidRide2]

I'm hoping it went out the exhaust????