99 3.0 idles high
My engine idles very high upon starting, and I've checked or replaced pretty much everything I can think of, the engine WILL drop down after several minutes( I haven't actually timed it, but I'd say it's at least five minutes), and once it does, I can rev it, and it returns to normal. If I shut the engine down, and immediately restart it, it goes back to a high idle for several minutes before returning to normal idle. I've replaced the idle air controller, the throttle position sensor, the vacuum control solenoid(broke it trying to get the vacuum lines loose, cleaned the throttle body thoroughly, cleaned the MAF sensor, re-torqued the lower intake manifold, replaced the upper intake gasket, replaced the EGR gasket, cleaned the EGR, and tested it, checked all the vacuum lines and connections, and checked the amount of vacuum(my guage is pretty old, it's showing right on the lower line of normal, so I think it's ok0, I've tried isolating parts of the vacuum system, by unplugging and capping off the lines, no changes noted. It has shown trouble codes P0171 and P0174, which is system adaptive fuel too lean on both banks. I recently replaced my heads, and rebuilt the injectors at the same time, everything was running just fine afterward, but I'm wondering if maybe running some seafoam thru the fuel would be a good idea. Any thoughts/information would be GREATLY appreciated. Sorry for writing a novel here, but I wanted to try giving a decent history. Thanks for reading.