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HELLO I JUST BOUGHT A CADILLAC BROUGHAM AND IT HAS THE 307 V8 OLDS IN IT AND CAR RUNS ROUGH WHEN RAN ALONG TIME CAR ENGINE REALY SHAKY AND ANNOYS ME THE MOST IS WHEN I SHUT THE CAR OFF THE ENGINE STILL RUNS AND BOUNCES AND CUTS OFFF.. I DONT KNOW WHAT WRONG WITH IT :confused:
 

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You need to do some diagnosis to determine the problem, is it overheating?(compression test, check tune up)
Something wrong with the distributor once it warms up?(bad module or pick-up coil)
Carb dirty and in need of rebuild?
Clogged fuel filter?

Lots of things are a possibility, but you'll need to do some checking and report back for use to help you out.

If, by chance it needs a timing chain, it is not the end of the motor, the chain and gears can be replaced.

If you should need to replace the motor, any Small Block Olds engine will bolt right in place of the 307. A 350 or 403 would be the most common.
 

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Old(s) Fart
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I doubt it is the timing chain. The 307 uses the CCC electronic Qjet carb and has about 50 miles of vacuum lines. If any one of these is bad (and likely more than one is cracked) the system will run poorly. Problems with the vacuum lines rarely result in codes stored in the computer, so you need a factory Chassis Service Manual and a mechanic who understands the CCC system.

Once all the vacuum lines are correct, then you need to adjust the carb. The procedure detailed in the factory manual MUST be followed exactly, otherwise you will not be successful. You need to properly set the mixture control solenoid inside the carb, you need to properly set the throttle position sensor, and you need to ensure that the A.I.R. system is working properly (that was the problem on mine). It took me about two months of weekends to chase through the problems on my first 307 car, but once the system is dialed in properly, it runs great. Mine ran for two years with no problems (until the 200-4R trans fragged...).
 

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Old(s) Fart
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techinspector1 said:
Avoid those fosdick Haynes and other aftermarket manuals that basically say "Disassemble", "Re-assemble in reverse". Worthless in my opinion.
I agree, but sadly the GM factory manuals have deteriorated to that point. For example, I have Chevy truck service manuals from the 1950s, 1970s, 1980s, and 1990s. The quality of the information and illustrations in these manuals have consistently degraded, while the manuals themselves have grown in pagecount. The 1950s manual, for example, is richly illustrated with photographs. The 1970s manual has a mix of photos and highly detailed line drawings. The 1980s manual has only drawings, and the manual for my 1999 truck has only a limited number of small drawings that are so lacking in detail that they wouldn't even qualify for a Powerpoint slide. The lack of detail in the text equally degrades over the years. The 1999 manual has degenerated to very top-level steps and flow charts. The unfortunate thing about the flowcharts is that EVERY one of them has a step at some point that says "replace computer with known good unit and test again". Easy for the dealership, tough for the home mechanic.
 
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