well it was running fine then i decided to do the long need valve cover gaskets so i did these then my car was hard to start and threw a lean bank 1 code and multiple missfire codes it also turned on my traction control light and a code 1652. since then i have cleaned the terminals did the gaskets and a full tune up i also checked resistances on the coils. and all seems to be in check but it still idles erratically. yes being a series II L67 i did need to remove the two map sensors but i went over all the vacuum hose three times and all appears to be normal and back to original. so now i am at a lost and need help.

also i did the coupler on the */C and didnt remove anything besides the snout.

Make sure the O2 sensor harness isn't touching a spark plug wire, and check for vacuum leaks again.

Use carb or intake cleaner while the engine idles. Spray it lightly on each vacuum connection and sensor vacuum connections. Check the T fitting under the nosedrive of the SC as well.

thanks for the tip willwren i just double checked it and i did not find any vacuum leaks could it posiblly be a PCV or EGR?

update i now checked the pin on the EGR valve and the PCV both are ok, but it still idles erradically. still at a loss as to what else maybe causing this

DTC P1652 Cooling Fan Relay 2 Control Circuit

Seems unrelated to the idle issues. Did you move or disconnect any plug wires to get the valve covers off? What about fuel injectors? You'd normally think that would cause a rich condition (unburnt fuel from mistimed injectors or plugs) but it doesn't hurt to check.

If the lean condition persists, it'* usually going to be a vacuum leak or electrical problem.
Boost fought a lean bank 1 for some time.

Some other things to check (have caused similar issues in the past) are your batter connections and alternator condition. You don't have a voltmeter on the SSEi, but do you have a scantool to see the alternator output? Have a voltmeter? What is it at idle?

You may ultimately have to pull your plugs and 'read' them. They may pinpoint the problem area better. Number those suckers as they come out.

well lean bank 1 ended up being corrosion on the battery terminals so i cleaned them and all other ends. that helped greatly then i did the snout and that helped then the tune up helped
but for one reason or another i cant get this to idle correctly.

How old are the plugs and wires, and have you checked the coils using the procedure in Techinfo?

Good work so far. We're whittling away at it.

I have been on the Phone/ IM with Mike the past few days....that is when he told me about the Lean Bank One and the other code as well....he cleaned the Cables, and the lean bank went away

his plugs were original with 99K and i told him to replace with TR 55'*...Mike told me that he just replaced the Wires not long ago

i gave him the Coil Testing Procedures earlier in the day, but never heard anything further

i just replaced the original plugs and wires for NGK TR55'* and ac delco wires. like i previously stated i did your vacuum check and all seemed good no surges or sputters as the carb cleaner was sprayed. all plugs wires and hose are in correctly positions i also cleaned the battery terminal ends.

yes pat sorry i haven't gotten back to ya but yes i checked the coils out and they are all good and not out of spec.

thanks so much for this one on one willwren hope fully we can get this figured out.

heres a thought could it be a ICM issue?