1997 Ex 4.0 SOHC running alittle rough

[Scout3]

I recently bought a 1997 Explorer for my son. It has the 4.0 SOHC. I bought it from a friend and he told me it would get the CEL light when it got cold. Sure enough this past week it happened with the P0171 and P0174 codes. In reading on this forum I am pretty much sure I need to change the intake gaskets. It had been running pretty good even though it had this problem. About two days ago, my son told me that sometimes when he gave it gas while cruising about 35 that it would not accellerate at first and then surge and accellerate. I drove it but did not notice anything as the problem is intermittant. I did notice that it does not start quite as easy as it did before. I disconnected the MAF while it was running and it had no or very little effect. I am going to start working on it over the Holidays and I'm starting to study up on possibilities. I read on the intake gasket change that you need to change the chain tensioners. Is this necessary? Also do you need to change the lower intake gaskets as well or is the problem pretty much the upper gaskets. Where is the best place to measure engine vacuum? All the hoses look good, I just would like to verify what it measures. Any suggestions or help would be appreciated.

Ed

 

[2000StreetRod]

Intake gaskets & tensioner

I recommend replacing the hydraulic/spring timing chain tensioners every 75,000 miles. The 00M12 kit includes the front hydraulic tensioner, the upper and lower intake manifold gaskets and the oil galley volume reducer. The cost of the kit is less than the cost of purchasing the hydraulic tensioner separately. The lower gaskets are almost as likely to leak as the upper. I suggest doing both the upper and lower gaskets: Starting my 00M12 Installation

If it's been more than 30,000 miles since the fuel filter was replaced you might save your fuel pump by replacing the filter: Why change fuel filter?

I suggest that you clean your MAF sensor with MAF sensor cleaner.

The 97 has the variable intake system which becomes active around 3,000 rpm. Make sure the rod/lever that connects the vacuum motor to the intake runner control is connected.