97 Blazer 4.3 start issues

OK.. 97 Blazer, 4.3 Vortec, 118,000 miles. Over the miles, alternator, water pump, a/c compressor, transmission, another alternator, fuel pump (at 102,000 on the fuel pump).
What happens is, when starting, I usually have to do it twice. The 2nd time I hit the key, it "catches", slight shake, as if it is not running on all cyls. IF I press the throttle slightly, it will run rough for 10 seconds or so. then smooth out.
After that it idles fine, in gear (auto trans). Drivability is fine. Fuel economy is same as always - I track that pretty carefully.
It does this first star in the morning, and at other times after being run a while. Occasionally, it just starts "properly" - brief touch of the key to start position, no shaking/ weirdness. I can't correlate it to "warmed up", start after trips of various lengths, etc.
No check engine light, or other dash lights for that matter. Gauges all normal. . Thougths? Guesses?
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On Tue, 15 Feb 2005 22:27:28 -0600, Merlin donned fireproof underwear and scratched on the wall:

IMO, starter.
Good luck 'cause its a bitch to get out.
I think that happened on my Jimmy at around 120K.
--
kai
www.perfectreign.com
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Hmm. Don't think so.. it cranks over fine - the issue is it sort of stumbles the first 10-15 seconds of running, or stalls, unless I apply pressure to the throttle.. and then I discovered if I turn the key to "run", wait 10 secs, and then crank, it doesn't do this. At least that's the early conclusing.

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It might be fuel pressure regulator or fuel pump. fuel pressure regulator is supposed to be closed and hold pressure when the car is not running. if it is leaking, it mihgt not hold enough pressure and it mihgt take some time to get enough pressure.
fuel pump: the fule pumps are considered bad if they die all the way. however, sometimes, they might leak before dieing all the way, so again you donot have enough pressure at the beginning to run properly.
one of them might be your problem. I donot know if there is an easy way to test it other than connecting a pressure gauge to the fuel injertor line. it should has a pressure relief valve on the line.
good luck.
Merlin wrote:

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I may have another tidbit of info. IF I turn the key to run, wait about 5 seconds, and then start, it starts properly. Hmm. Fuel system losing pressure? Ian? Is there a check valve somewhere?

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Install new clean fuel filter, then check fuel pressure. Check O2 sensor voltages after hard start. Low readings indicate rich condition. High readings indicate lean condition ie low pressure. Helps to have scanner and fuel pressure gauge to diagnose this problem.
wrote:

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I'm considering a scanner anyhow - but thanks, will advise. The fuel filter is a good plan also - won't hurt in any case.

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