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Aber71 09-01-2017 11:27 AM

idle issue
2003 4.0 sohc.The issue I'm having is when the pcv vacuum line is hooked up my truck wants to fall on its face. when I unplug the line it runs but keeps reving up and down. do the verge its going to shut off then catches itself. Any solutions? And there is no codes

EaOutlaw1969 09-02-2017 01:39 AM

Re: idle issue
Have you smelled the oil lately, if the oil is contaminated with fuel the added fuel mixture can cause weird problems.

If you smell a lot of fuel in the oil, obviously you will need to change the oil and filter but you will also need to find the source of the extra fuel ending up in the crank case.

leaking injectors can bleed all the pressure off so a fuel pressure check may be in order.

When I used to have a 4 gas analyzer I would use the probe to check for excessive hydrocarbons in the crankcase.

Back in the day there was a procedure I would go by but it has been so long I forgot the specifics. I think the engine had to be shut off for 5 minutes and the hydrocarbons in a normal crankcase would be under 300 PPM.

I mention the 4 gas analyzer because if you have emissions inspections in your area you will have some shops around that still use a emissions analyzer to test the crank case fumes if you do not trust your nose.

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