Engine sputtering and running rough

[jabbott126]

So i have been working on this 91 plymouth laser RS fwd turbo. i have a small 16g on it , A straight pipe exhaust, and a boost gauge thoses r the only mods.

Heres whats up
the other week i took the laser out on the track for some speed lapping. I was holding my speed in 5th gear, i looked up at my boost gauge and it said i was pushing 20lbs?!?!? (not sure why there was no fuel cut?). After about 20 seconds i heard the exhaust sputter and my car got louder. I slowwed down and rolled down the window to listen and it was running realy rough. so i got it home barley. i would drop rpms and almost stall if i didnt keep on gas. also it would rev up very slowly. also exhaust would sputter like a machine gun after like 2,000 rpms. i found a melted spark plug ad i replaced that then i replaced the coilpack still runs rough.

So as of right now im not sure whats up with it. I can start it but it runs like crap and stalls easliy without keepin on the gas..

let me know what you guys think

thanks

 

[brandonwh64]

Do a BLT and a Compression Test. Melted spark plugs sounds bad and it sound like the car leaned out due to over boost but i could be wrong.

 

[GRAVEDIGGER]

Do a BLT and a Compression Test. Melted spark plugs sounds bad and it sound like the car leaned out due to over boost but i could be wrong.

I agree. It's time to do a compression test for sure. With a melted spark plug it was definitely hot. You may have melted a piston too.

 

[95eviltalon]

Yeah do a compression test for sure. How come you didnt let off when you noticed the spike?

 

[jabbott126]

i noticed the spike right as it happened.

 

[overkill]

Piston is most definitely melted if the spark plug was, but a compression test would verify like everyone said. You can rent the tester from Autozone if you don't have one.