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iTrader: (2)

I replaced a broken spring, put everything back together and it runs bad. Runs fine under normal driving, but bring up rpms under load and it backfires and runs horrible. I think I may have a collapsed lifter. Any input would be greatly appreciated!

UPDATE- Runs great in open loop. I changed the map sensor thinking that was the problem initially. It seems to run better with the MAF unplugged in closed loop, but not much better.

Burken01

iTrader: (88)

Take the heads off to see what damage is done.

That's the only way to really know..

crainholio

iTrader: (2)

Before you pull the heads, run a compression test on the cylinder w/ the failed spring and a few others for comparison. Should be within 10% of each other.

Disconnect the fuel pump, and hold the gas pedal at WOT during cranking.

Report back w/ findings...bad compression points to a damaged valve and/or piston, good compression points elsewhere.

crainholio

iTrader: (2)

PS: could be as simple as a damaged plug wire when you removed it...

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update in original post