1985 4+3 running bad
Thread Starter
8th Gear
Joined: May 2008
Posts: 8
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1985 4+3 running bad
Trouble began after changing the intake manifold gasket. Rough idle, varies around 500 rpm. When driving the car as soon as I let off the gas , car stalls. No check enginge light at all. What's my next step? All surfaces were totally spotless for the gaskets. Had to change the gasket for anti-freeze leaking @ #1 cylinder out the top.
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
Trouble began after changing the intake manifold gasket. Rough idle, varies around 500 rpm. When driving the car as soon as I let off the gas , car stalls. No check enginge light at all. What's my next step? All surfaces were totally spotless for the gaskets. Had to change the gasket for anti-freeze leaking @ #1 cylinder out the top.
Safety Car
Joined: Oct 2007
Posts: 3,816
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From: :45 minutes from everywhere / E-I-E-I-O
I know you don't wanna' hear this, but I'm bettin' you didn't get a good seal somewhere, and you got a vacuum leak.
Crank up the idle speed to get a steady idle. Brick on pedal screwdriver in linkage, and then fish some starting fluid/propane/carb cleaner around ALL joints and vacuum hoses.
RPM revs = vacuum leak.
Crank up the idle speed to get a steady idle. Brick on pedal screwdriver in linkage, and then fish some starting fluid/propane/carb cleaner around ALL joints and vacuum hoses.
RPM revs = vacuum leak.
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
This sounds definately like a vacuum leak....the most problematic areas are the metal pcv line that runs across the driver side valve cover and the small hose (2 inches long)that hooks to the intake, and the hose that hooks to the pcv valve itself. The small hose has a half inch inside diameter, make sure you get a high quality one if you have to replace it. Spray some starting fluid around to isolate your problem. Happy hunting!
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Safety Car
Joined: Oct 2007
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From: :45 minutes from everywhere / E-I-E-I-O
You can replace parts till you need a sweater in Hades, but if you have a vacuum leak, it ain't gonna' run.
Thread Starter
8th Gear
Joined: May 2008
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checked motor with Snap-on Brand Modis computer terminal. Code 12 came up on the terminal, oxygen sensor said it was running lean. Checked all the vacuum lines lines again to know avail. Removed the distributor cap, and looked great. Removed the tps sensor plug, motor reved up, and accelerated smoothly. Drove car and as soon as you let off the gas for any length of time it quits instantly. It has power and speed is not an issue. Lost for words now.
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
Rough idle, varies around 500 rpm
checked motor with Snap-on Brand Modis computer terminal. Code 12 came up on the terminal, oxygen sensor said it was running lean. Checked all the vacuum lines lines again to know avail. Removed the distributor cap, and looked great. Removed the tps sensor plug, motor reved up, and accelerated smoothly. Drove car and as soon as you let off the gas for any length of time it quits instantly. It has power and speed is not an issue. Lost for words now.
Bad injector on the lean side?
???
Last edited by schrade; Jul 9, 2008 at 09:17 AM.
Le Mans Master
Joined: Dec 2005
Posts: 8,561
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From: Communist Colorado
Well, you know it has to be something in the manifold gasket change operation if it wasnt present before. Re-check all the injector connections, and vacuum lines. Also check any other electrical connections at the sensors. Did you remove the screws holding the TPS? If so, it needs to be repositioned using a diagnostic tool.