Hey everyone,

I just finished up replacing two cracked heads on my 2001 1500 5.2. About a month ago I realized something was wrong because it started progressively using coolant more and more until it was using 1/2 gallon per week (about 350 miles). Over the weekend and up until today I tore the engine down, bought heads from the local machine shop who ordered the stronger casting heads and finished buttoning it up today. It runs good, seems to have to same amount of power as when I pulled it apart but I can not get the idle to come down to where it should be. It is idling between 850 and 1000 rpm. I went over eveything and checked all my vacuum connections, everything seems to be sealed. The only thing that is different from when I started is that I now have a gasket sealing the air filter to the throttle body which was missing previously. Any suggestions would be appreciated.

Thanks,
Frank

 

With the engine fully warmed, and in gear, you should idle around 700 or so. If you have a GOOD scanner, you can check data, and see what the PCM thinks the engine is actually idling at, what manifold vacuum is, and what the target idle speed is.

 

I will try to get a hold of a good scanner but it is a manual so the idle doesn't drop. If I let the clutch drag and bring the rpms down, as soon as I push it back in the rpms go back to 850-1000

 

have you disconnected the battery to reset the computer yet?

 

Not yet, I didn't even think of that

 

Turned out that even though the intake was torqued to spec, it was still pulling air though the gasket. I tightened up the intake bolt and its running perfect

 

That's good to know for future reference. I plan on building up an engine for the truck in the future and heads are definitely going to be a thing that I replace.