Why a 1969 gto stalls when you press the gas?

Answer 1

Check the following: fuel squirt from accelerator pump circuit in Q-Jet carb, correct ignition point dwell (30 degrees), pull off vacuum hose at distributor at idle & gently suck down a vacuum; it should speed up the engine slightly- indictating that it works the advance pull; if it doesn't it's ruptured. Check base timing at idle & it should be around 8 degrees with the vacuum advance hose pulled off at the distributor. Slowly rev up the engine & watch for the timing marks to advance on the pulling while using a timing light. One thing about a nearly 40-year old distributor: the dwell should be 30 degrees at idle. Rev up the engine while a dwell meter is hooked up & see if the dwell changes more than 2-3 degrees. If it does it's worn out & should be replaced. Pontiacs were also bad about the roll pin that holds the gear onto the distributor shaft cracking & the shaft would "walk" around, changing the base timing & making it sluggish. Sometimes they'd pop & the shaft would remain stationary & the engine would quit. Hard to find & easy to fix. Onemore thing: Pontiacs were bad for timing chain wear. Place a breaker bar & socket on the balancer bolt, gently turn in the direction of normal rotation until the slack is taken up. Then also gently slowly turn the bolt backward against normal rotation & see appx how many degrees of slack you have. If it's anywhere approaching 30 degrees, then valve timing will suffer & a stumble will result. One final thought (of many): check sparkplug wires with an ohm meter. New they're about 6-7K ohms. With any time on them & high underhood temperatures they age quickly & if they're anywhere near 12K ohms or more they'll cause surging/stumbling & may crossfire. Good luck.