P0171 P0300 melting plugs

[19gtp98]

Well i have a 98 gtp with the 3.4, custom air, ported headers, high flow cat and exhaust, screen removed, and at one point the reprogrmamed chip. One day i was running it hard and at high speed service engine appeared took it to my mechanic fried spark plugs 3 and 5 he said my chip most likely leaned it out removed chip, pu tin new plugs, same thing 3rd cylinder fried plug so we checked the fuel system changed the filter clean injectors, and then 3rd time was a charm 3 and 5 piston popped the crack iin the top right hand side of the piston, went all out got a full warranted long block installed and started it drove it down the block and then bang again the plug melted what would cause this lean condition it would not be the missing screen at the maf? now i have a tap that sounds like it comes from the fuel rails, any tips out there??

[BIG-L]

What kind of reprogramed PCM do you have in your car??

[19gtp98]

The reprogrammed one was from e-bay and he said it was from 3800 performance with the skip shift, limiter removal, normal stage one stuff. but i no longer have that in. the stock chip has been installed.

[BIG-L]

Originally Posted by 19gtp98

The reprogrammed one was from e-bay and he said it was from 3800 performance with the skip shift, limiter removal, normal stage one stuff. but i no longer have that in. the stock chip has been installed.

Must be a DHP PCM.

Only way to tell,is to have it scanned and see what your fuel and timming tables looks like.

I know that the Intense PCM was running way to much timming @ WOT, 23 degrees and was popping pistons.

~Larry~

[19gtp98]

But why after going back to stock am i still running lean and still melting plugs?

[BIG-L]

Originally Posted by 19gtp98

But why after going back to stock am i still running lean and still melting plugs?

Could be,that you have a problem with the Injector's on 3 and 5

Again,the only way to tell,is to have it scanned and see what your Fuel Injector Pulse Width look's like.

Injector Pulse Width - Must be less than 23ms at 5200 rpm, 21.4 ms at 5600 rpm, and 20ms at 6000rpm. Anything equaling or greater than these values at these RPMs indicate that your stock injectors have gone static (i.e. always on at WOT).

[19gtp98]

thanks that helps out alot i was driving around with the scanner on and then going back and trying to understand alldata's info with my readings , but that will help out alot i might just have to take off work early and check that out thanks again

[19gtp98]

one other quick question spark was at -23 on the scanner is that normal?