60DRB

I recently was reading a thread about a random miss. Guy had done all sorts of trouble shooting to include inspection of the lifters. Turned out to be the evap purge valve was bad.

Jwill517

Went out and got a vacuum gauge and it holds right at 18 with no fluctuation.

papa tiger

I went back and re-read it. Your cylinder balance testing was evident of a worn motor ? Possibly a new cop and spark plug ? Can you look at your PID graphs. Still believe it to be an air issue possibly intake leak around MAF or faulty.

Jwill517

I've replaced all the c.o.ps and spark plugs (motorcraft). Ford said they couldn't tell if the motor was bad or do anything else until a compression test was done and if it was good they would go to the next step in the manual. Brought it home and compression tested good. Vacuum pull was steady, rpms stay steady. Plugs show lean on 5&6. Spraying brake clean does nothing to the idle. Sprayed around the intake, hoses, connectors. Inspected, sprayed, and wiggled the purge valve with no changes. What's next?

Jwill517

I will be able to check the pids when my buddy gets back from out of state but right now I can't.

VTX1800N1

New front O2 sensors virtually eliminated my rough idle. No codes before they were replaced, though I still have a large long term fuel trim imbalance between the banks.

papa tiger

The O2's do set the stoic, U should see evidence on the pids. Graphing the pids can really help to tell if it has out of tolerance, especially if you have a truck to compare it to. Many times the electronics will code when they burn out and not when they are out of tolerances maybe due to a connection.

VTX1800N1

The STFTs oscillate nicely now that I have replaced the primary O2 sensors. The LTFT for Bank 2 is at +14 at times while Bank 1 is near zero. I replaced the fuel vapor vacuum hose today and the engine runs noticeably another at idle. You can barely tell it's running at idle. The vacuum nipple broke off the intake manifold. I got some plastic weld and reattached it. There could have been a crack in the nipple or the hose could have been leaking. I'll have to check the fuel trims again and see if there was an effect.

VTX1800N1

Jwill517

I hooked up a vacuum gauge and it sits still right at 18, no fluctuation at idle. Looked all over for a leak and can't find one. Could an intake leak still be possible?

Thanks for the info I'll definitely look into the pids and O2 sensors. I'm going to swap injectors and see if the lean condition follows the injectors too.