Rough Idle/Bucking
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From: Seymour, Indiana
Rough Idle/Bucking Well i went to Town then came back. hour later i had to go back to town. I started my car it showed 160 dregrees on the temp. I was pulling out of driveway on kind of a slope and i let out on the brake alittle and it started like bucking. And once it gets 215+ it starts having rough idle.
What could be the problem it runs perfect when its at like 180 Degrees.
What could be the problem it runs perfect when its at like 180 Degrees.
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Which is all perfectly normal operating temps for an LT1. I'd say that either you're running too low octane of fuel and it's just having problems igniting, or similar situation but your plugs/wires are kind of old and aren't being able to ignite all the fuel.
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From: Seymour, Indiana
Could be 02s? its got 118k miles
Shobox Says
Something else to consider, is that when the engine gets to ~220º (even before the stock fan ON temp of~226º) and you are at MAP loads of 70Kpa or more, the PCM begins to retard the timing. That is one reason why people feel their cars don't run well when they are hot. The GM folks built the retard into the spark tables because when the engine is hotter, there is more chance for spark knock. If you can keep the temperatures from getting up into that range, then you might feel more power when you need it.
