My 2000 DII has been doing well but recently my idle went cray when sitting still. Seems to drive fine, accelerates, cruise, like normal.
I have done a lot of maint over the last year or so and she was running great, then got a ton of misfire codes, pretty much every cylinder, and sounds like a car with a modified cam at idle. this came on all of the sudden, good one day, bad the next.
Ignition coil(s), wires (tried magnecor and NGK), Bosch Plat plugs (same ones I have used for years), O2 sensors, all new within the year. 2 years ago did the head gaskets and changed appropriate seals, sensors etc. Engine is clean minus a valve cover leak on the left side.
New throttle position sensor, Idle valve control, purge valve, crank shaft pos sensor, etc
Has about 170K on the motor. I had some weird starting/electrical issues a few months ago that I trouble shot to bad negative battery cable, wasn't tightening on the terminal, as well as redoing the under hood grounds. Thinking there's an electrical issue, relay, wire ??? under the hood that is causing bad communication with the ECU resulting in weird idle and misfire codes??????
Any ideas/help would be greatly appreciated. I am deploying this summer and wanted to pass the ol D2 off to my son for him to use while I was away. Been good up to the this point overall, now I am at a loss.
thanks
Rob

 

Get the codes read and post them please.

 

While going over harnesses take a look at CKP sensor/wiring for security and condition if not done already.
......

 

Today's codes, no misfire codes which is good I guess.


P0171 System too lean (bank 1) Multiplication injector adaptive fuelling - lean limit
exceeded LH bank

P0174 System too lean (bank 2) Multiplication injector adaptive fuelling - lean limit
exceeded RH bank

P1171 System too lean (bank 1) Additive injector adaptive fuelling - lean limit exceeded
LH bank

P1174 System too lean (bank 2) Additive injector adaptive fuelling - lean limit exceeded
RH bank

 

Vacuum leak.
Check the hose that goes to the brake booster.

Check all the vac hoses. You have a vacuum leak.

Also make sure the plenum is torqued properly to the manifold.

Check the fitting from the mass air flow sensor. That might be sucking air too.

 

x2 on what Jfall said. Just finished chasing down some of these codes myself. Check 'em, and torque 'em!

 

Did a visual inspection of vacuum lines. Not all of them are 100% visible. Torque on manifold is good, MAF connection is good. Is there a better way to verify there is not a leak?
Thanks

Rob

 

spray around the manifold base with wd40 or carb. cleaner if the idle goes you have a leak

 

Also check around the exhaust manifolds. A loose connection btwn the exhaust manifold and down pipe can also contribute. The passenger side gasket was shot, which contributed to the 1174 code in my case.

 

Will Do. found a broken bolt on the exhaust manifold, pipe connection which gives a slight leak, other two bolts are in and tight as well as a bolt out of the L/H exhaust manifold mount to the head.

Working head bolt now, broken bolt at connector may not be so easy...