Hesitating and stumbling on warm startup

DropSVT

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Hey guys I'm in need of some help. I've done numerous searches and can't find anything groundbreaking on my problem.
My problem happens after I drive the car for a bit and turn it off. When I start it back up it hesitates, stumbles, runs lean enough where my wideband can't read it, and is at -10 vac instead of the average -18 on the ol' boost gauge. After about 5 minutes of letting it shake around it clears back out and drive on like nothing happened.
When it first happened It was only after 5 min of it being off and I thought I had lost my pumps and needed a tow. Thought maybe because I was on a slope it lost its gravity or something but i was wrong when it happened again the other day after parking to take some pictures.
Does anyone have any ideas as to what's causing this? I replaced my o2s in August and thought it could be those but I'm not sure. By the way I can hear the fuel pump when I turn the key on so I know those are working currently.


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2fst4urtrk

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I had my "y" connector in the gas tank pop off and i had to limp the car home. Once it popped off i couldnt give it any gas just idled home
 

nxhappy

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is it idling above average? You may have a vacuum leak. Check all vac lines.

any check engine codes? Have you checked the spark plugs ?
 

nxhappy

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also, coil on plugs can cause a stumble. Pull them out, test the ohms.
 

Bdubbs

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Is ~18 normal for vacuum? Stock cams? I always thought 20-22 vacuum is normal.
 

DropSVT

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Is ~18 normal for vacuum? Stock cams? I always thought 20-22 vacuum is normal.

Yeah so I've read but there's a few of us with -18ish but it could be something up with my gauge. It used to be at ~20 before swapping my worn out eaton for a like new one and I redid the swap 2 times thinking I had to of missed something and ran leak tests and there's no vacuum leak. even made hella good power with it idling at -18 so that doesn't bother me.
is it idling above average? You may have a vacuum leak. Check all vac lines.

any check engine codes? Have you checked the spark plugs ?

While it's doing this it's hardly running bouncing between 250rpm and 800rpm and my vac goes down as it stumbles. I'm sure it's not a vacuum leak or it would do this all the time, it only does it on a hot start up and runs like it's got no gas for like 5 minutes and then clears out and is fine. I'll check engine codes and replace o2s and see where that takes me.
Funny enough last time my car was running like this it's when my air filter fell off it's mount lol


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nxhappy

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first simple check would be spark plugs

If you had a vac leak it would be idling high, not low
 

03 Zinc

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first simple check would be spark plugs

If you had a vac leak it would be idling high, not low

I have a similar issue... mine is from a cold start... sometimes it will crank up and cut right back off but if I hit the gas a little it will start running fine.... then after a few seconds it will like surge jumping in rpm and dropping back down almost turning off.... I have yet to figure this out...It only does this once a day from a cold start.... I have cleaned the MAF, TPS, Throttle Body, checked connections
 

nxhappy

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plugs and cops can cause all sorts of shit storms. really easy to check, and couldn't hurt ...
 

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