Loss of vacuum

J

Joisey Jim

Guest
I was having problems with Code 181 (running lean bank 1), but after I changed plugs & the 02 sensor it ran better. Now it starts and runs ok at first, but by the time it warms up the vacuum drops to around 12 and the car has no power. I can't find any vacuum leaks, or bubbles or discoloration in the coolant; but when I changed the oil at the week-end is was more brown than black. Head gaskets? This 93 does have 207,000m on the original gaskets.
 
Compression test

I would recommend doing a compresion test or at least a cylinder balance test to see if you have a weak cylinder(s).
Your oil should never look brown. That would indicate coolant getting into the engine either from a blown head gasket, a leaking intake or timing cover gasket.
I was getting a slight milky sludge on the oil filer cap that turned out to be a leaking intake manifold gasket.
Once I replaced the gaskets, no sludge at all.
The 3.8 is prone to leak at the coolant passages of the intake into the oil galley.
 
I'll try the compresion test, but that's an SOB job with our plug locations. I can't do the cylinder balance test either as the engine won't run stable long enough. I also revisited the waste oil and it's certainly not like 'chocolate milk' as someone had advised was a sign of HG failure. I realized I changed the oil because I was under the car anyway and it's been 3 months, but the actual mileage was only 2,000m. What happens is the car fires up right away, but then the vacuum gauge drops to about say 7-10" and you can definitely feel the exhaust pressure drop right off. I wonder if a cat (original with 207,000m) has broken up and the debris is blocking the exhaust. There is definitely some backpressure in the system because exhaust soot & condensation is weeping out of the rear of the resonator joint & the joint where the pipe splits to the mufflers. Anyone else have a similar problem?
 
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