99 regal gse. I recently swaped a 100k mile engine/trans into it. It ran/shifted weird for a while which I asume is the computer re-learning the new engine. I drove it normally for 150 miles and everything runs/shifts/drives great.

I decided yesterday to see what this l67 is made of. Turned a corner onto a suitable no traffic road and from a 10mph roll I put the pedal to the floor. Pulled hard as hell till the tack hit 5k in second gear. Boost 10.5psi. 94 octaine gas. The power went flat and the check engine light started blinking at me. Uh ho. I let off the pedal and coasted for a bit. The light stoped blinking and is now on constantly. Still runs and drives as good as it did before.

I'm goint to take it to autozone after work to see what code(*) tripped. In the meantime, any ideas what could have went wrong bad enough for the light to start blinking at me? I have to asume that indicates a serious condition.

Blinking indicates a potentially catalyst damaging condition. Usually the biggest offender is a misfire.

I think autozone will pull either a P0300 which is a multiple misfire, or P030X, where X= the cylinder that misfired.

I am curious to see what comes up, if it misfired, there may be other codes that flush out as well to give you an idea what happened.

I got $5 that its a misfire.

Well i drove it after work. Stoped at autozone. Misfire in #1. No other codes. It drives fine, runs smooth. The instant MPG reading is the same as before at a steady speed.

BUT It shakes and the misfire is aparent the instant i get into any boost at all. The gauge blips .2 PSI and i can feel it. Step on it hard and it is really obvious.

The plugs and wires are new with the engine swap. I dont remember what type of plug exactly but it was a popular recomendation on this site. 108 or 208 maby.

I am going to pull the plug and inspect the wire. If those are fine, that only leaves a coil right?

no, misfires can be fuel related as well or intake gasket. i would go in this order which is alot easier if you have your own tool. move the coil pack and see if it changes, then go to moving injectors. check for bad orings.

The intake gaskets are good. I replaced those before I put the engine in. Used the updated gm aluminum ones. I bought new o-rings for the fuel injectors too because when I pulled the fuel rail they were hard and not round anymore.

I pulled the plug and found what I believe to be the problem. I have never had a plug fail on me before but it sure looks like this one did. What gets me is why it runs fine untill I really get on it. I will pick up a new plug tomorrow after work. If that doesn't do the trick I guess I'll swap coils and see what happens.

Well that plug was at least part of the problem. I took one of the plugs out of the old engine, gapped it and put it in there in place of the cracked one. It is better, but i can still feel it after about 3 lbs of boost. The plug i took out is a copper autolite 41-601. The one i replaced it with is a NGK OEM type. Looks like an iridium plug.

I will go get a new plug after work tomorrow, but there is probably more to the issue then a cracked plug.

I am also going to order a scanner tonight. I dont feel like going to autozone 10x for them to read my codes. Any recomendations on an afordable one that will read live data? Im also interested in watching o2 sensor readings and ignition retard.

if you got an android phone torque is good. it says you can record o2 and kr but i never messed with it. pretty cheap to get into too 5 for the app and 20-50 for the bluetooth adapter the cheaper ones are fairly slow to respond

i dont have a sc engine but to me that looks like its saying the voltage would rather go though the insulated boot than the plug, doesnt seem like the right plug or they are no good. plus the more you run like that the more you get carbon on the boots and the better the boots start conducting

I am driving my hooptie truck to work till the issue is sorted out. So the only miles on the car in its condition are the couple to get home and my test drives so maby 10 miles. Stopping today to get a replacement plug and 2 extras. They came in a box of 6 so if that one was dropped in the parts store, there'* a chance more then one is cracked. After I replace it with the right one I will go from there. Luckily I have the coils from the old engine for troubleshooting.

Can a damaged plug like that one cause any damage to a coil? Would be a weird coincidence for more then one thing to fail at the same time.

This is why I don't often beat on my cars. I just wanted to see what its capable of.

i havent seen where it does anything to the coil. do you know how many miles where on the new engine? you may just find out some stuff was bad before you got it. also sometimes the tabs on the icm corrode from being old or sitting.

they dont put the sc'* on for no reason as long as you have a truck to drive give her heck, the 3.8'* are pretty tough. now its the weak fwd transmissions i would be worried about.