Car dropped 250 RPM and is now stuttering

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WSUTARD

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Can anyone advise me on where I should start in order to track down this issue that just popped up.

I was driving around today and things were going great. I stopped for gas and when I started the car back up I noticed that the idle revs we sitting at 500-450 instead of the 750 they are normally at. On the drive home I was experiencing some stutter (like surging but opposite, I was losing power not gaining it) under light load, specifically noticeable between 1500-2000 light throttle.

I'm not quite sure where to start. I'm letting it cool down now but it seems like all the plugs are connected still, which was my first thought.
 
A tad more info. Carb, ignition system?

Is it possible you developed a vacuum leak?
 
Bad Sport said:
A tad more info. Carb, ignition system?

Is it possible you developed a vacuum leak?
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Sorry. Eddy 1406. Ignition powered by MSD 6AL Digital with Blaster Coil.
All connections are connected.

I will check for a vacuum leak when I start it back up.

Plug wires are in tact and connected.

Distributor is locked in tight.
 
WSUTARD said:
Sorry. Eddy 1406. Ignition powered by MSD 6AL Digital with Blaster Coil.
All connections are connected.

I will check for a vacuum leak when I start it back up.

Plug wires are in tact and connected.

Distributor is locked in tight.
Click to expand...
Sounds like you got a bad load of gas.
 
retroron said:
Sounds like you got a bad load of gas.
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Well, my tank was 1/4 full when I stopped. It is my normal spot, Costco Gas, Premium. I guess its possible. Costco Gas around here is normally considered very good quality.

Also, my lines were full of good gas still but it started at the 500 RPM instead of 750.
 
Bad Sport said:
Yeah, just a thought. Start it and cover the top of the carb with your hands, does it stall?
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Every time I've had a problem like yours, with the same outline, i.e., just got gas, it's been the gas. And the last 2 times it happened its was Costco gas. Just saying
 
I'm not denying it. It has to be related. I can't even keep the car idleing now. Check out this video. Notice the Roma bumping up and down? My foot is steady on the throttle.

 
WSUTARD said:
If it is A gas issue, what do I do?
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Did you fill it? If it's water in the gas you could siphon some out and put it in a glass jar and let it set for a while, it will separate. Water is heavier than gasoline and will fall out to the bottom.
 
Bad Sport said:
Did you fill it? If it's water in the gas you could siphon some out and put it in a glass jar and let it set for a while, it will separate. Water is heavier than gasoline and will fall out to the bottom.
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YEah, its full. I guess I will try that.
 
WSUTARD said:
If it is A gas issue, what do I do?
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To me that sounds just like bad gas. So, you can buy some gas drier that will absorb the water (found that sometimes it actually works) or if you can live with it, drive it to empty and refill your tank with good gas. If you like living on the edge you can drain your tank. Might consider changing the fuel filter as well.
 
Do you have a mechanical or electrical pump? The easiest thing to do to truly see if it's bad gas is to stick the line into a can of good gas and run it for a few minutes and see if it clears up.
 
drain the bowl of your carb,..see what it looks like, got water or trash or good clean fresh petro gold??? then check for dead plugs,..burnt plug wires ect ect...my money on bag gas tho!
 
No burnt plugs or wires.
How long till the water separates from the gas?
IMG_2007.JPG
 
So it took 10 gallons out and I'm driving it around now to get it lower then fill it up. Wouldn't I see vapor out the tailpipes if it had enough water to mess up the engine?
 
WSUTARD said:
So it took 10 gallons out and I'm driving it around now to get it lower then fill it up. Wouldn't I see vapor out the tailpipes if it had enough water to mess up the engine?
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Not necessarily. Weather conditions play a factor as well.

Hopefully it is just a bad batch of gas.

Throw some Chevron, Shell, 76, Sunoco or Mobil in there and let's see what happens.
 
WSUTARD said:
Can anyone advise me on where I should start in order to track down this issue that just popped up.

I was driving around today and things were going great. I stopped for gas and when I started the car back up I noticed that the idle revs we sitting at 500-450 instead of the 750 they are normally at. On the drive home I was experiencing some stutter (like surging but opposite, I was losing power not gaining it) under light load, specifically noticeable between 1500-2000 light throttle.

I'm not quite sure where to start. I'm letting it cool down now but it seems like all the plugs are connected still, which was my first thought.
Click to expand...

Slap the crap out of it a couple of times and ask it if it's going to jerk that smoke wagon or stand there and bleed? :D

Make sure the choke is open all the way and while at the same time you give a good wide open on the throttle cover as much of the intake of the carb as you can.
Don't rev it too high, but just enough that you can stall it while still wide open with covering the carb while still enough RPM's to let it recover and keep running when you uncover the carb just before it stops turning.

This puts an extreme vacuum on the ports and jets and will most times suck crap through where it causing the problem. (even water)
 
Ok. Took 10 gallons out. Drove it to the station. Filled it up with Shell premium with some sea foam for the water. Driving it now. Waiting for all the bad gas to get out the lines and carb. Stopped to idle a little. Idles at 300 and makes this noise.
 
WSUTARD said:
Ok. Took 10 gallons out. Drove it to the station. Filled it up with Shell premium with some sea foam for the water. Driving it now. Waiting for all the bad gas to get out the lines and carb. Stopped to idle a little. Idles at 300 and makes this noise.
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Sounds like you have a dead cylinder, check and make sure all plug wires are on. Check the plugs see if you have a wet one then you can find which cylinder it is, and go from there.
 
fatoldguy said:
Sounds like you have a dead cylinder, check and make sure all plug wires are on. Check the plugs see if you have a wet one then you can find which cylinder it is, and go from there.
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Will do.

I just checked the timing also. It seems to be all out of whack.
I just had a carb shop tune this thing just over a week ago. They set the advance at 18 initial and the total was capped at 36 with an FBO plate.
At 750 rpm I'm at 10 advance
At 2200 I'm reading 50 advance.

I'm going to check this again.
 
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