# Verrry rough idle and car wont Rev past 1000 rpm



## fufhubbin (Jun 8, 2015)

Hey I was just driving and my car all the suddon wouldn't get over 1000 rpm really. When it idles it bounced from 200 to 500 rpm pretty rapidly between the 2. Car drives about 5mph or less and sustain idle for 10min plus even thou it it very rough. Long story short exact same thing happened 1 week ago.... check all the hoses and it was a vacuum leak on a hose which I fixed by triple wrapping it in electrical tape. I have double triple checked that area and every hose almost that I could see around the engine no sign of wear. 

After liking at stuff found out that 1 of the spark plugs is not firing....hooked it up to a different port on the coil pack and it sparks....and when we hooked up a different spark plug to that port on the coil pack and it didn't fire when on that port either. Don't know of this is cause the same symptoms as the vacuum leak cause they seem identical to the hose leak 1 week ago


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## fufhubbin (Jun 8, 2015)

Bump bump bump


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## fufhubbin (Jun 8, 2015)

1994 altima 72k miles.


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## rogoman (Dec 16, 2004)

Your engine does not use individual coil packs for each spark plug. There is one distributor and cap at the rear of the engine. Inspect the distributor cap for cracks and carbon trails inside. Inspect the ignition wires for cracks. If they look marginal, it'll probably pay you to replace all the wires, cap and rotor.

As far as the idle speed bouncing 200-500, it may be due to a vacuum leak in the intake system. Normal idle speed should be 650 rpm. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. A good place to connect to is the charcoal canister. There should be three hoses connecting the carbon canister. Two of the hoses go to a purge valve that's built into the canister. The second larger hose off the purge valve should be your vacuum line. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be around 21 InHg.

If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.


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## fufhubbin (Jun 8, 2015)

Thanks so much yeah there was probly a spark on all the coil pack plus maybe just smaller on that 1 and less obvious.


Any other tips on finding a vacuum leak besides the one mentions. I am going to show that to the dudes looking at my car. Its still stuck on aide of road I hope we can find it


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