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[amba]

Gave car an oil change yesterday and removed plenum etc to give all a really good clean,throttle body/plenum etc.

Now I have done this job numerous times and all went back together as planned.Car started and ticked over at nice steady 650/700 rpm with climate running.

Went to work last night and on the drive there ,around 50 miles car was smooth ,accelerated and generally performed as expected.On way home felt like it was running on 5 cylinders and tick over was uneven and didn,t seem to differ with or without climate as normall without tick over is slightly slower.

Have had a really good look and check around this morning.Car started from cold and ticked over around 1200/1300 from cold which then went down to 650/700 when warmed up but sounds again like only 5 cylinders and not smooth and responsive when flipped throttle.I have checked and tps/rear ram plug/rear vac pipe/idle control plug all connected correctly.No pipes are trapped ,plenum is seated ,egr vale pipe is secure as is brake servo vac along with front bagpipes and both throttle coolant pipes.Have even gone round with carb cleaner seeing if I have got an air leak but even that is not throwing up the problem

Am at a loss as to why a job I have done many times has now thrown up a fault with the car,or could it just be "sods law" and a plug has decided to die even though they were all replaced less than 4 months ago (around 5k).

Is something glearingly obvious I have missed...

[cem_devecioglu]

I had once  a similiar problem.. but diffrerently I had eml light.. which turned out to be disturbed injector loom and sockets..

if you dont have eml worth checking the ignition cabling and sockets also

[Cliffo B]

Any Codes?

[amba]

No codes and no EML has appeared .

Strange how a perfectly running engine ,after giving it a through "Spring Clean",now repays me by running so rough.

Suppose I could have disturded the main coil plug as it is at the back of the passenger side,but would have thought it would then run really bad.

Does start fine and tick over but a tad erratic even though ICV has been cleaned to within an inch of its life.Just feels like a cylinderr is not firing correctly.

[Kevin Wood]

Only thing to do is backtrack through what you've done and check everything.

Injector plugs all secure, including the multiway plug at back of plenum? (would expect and EML if not, but..)
Plug leads all secure at both ends and each plug connected to the correct coil post?
Coil pack LT connector secure?
Spark plugs OK and tight (possible one has worked loose).
No oil in plug wells?
All vac pipes and breathers secure? No air leaks?

[amba]

Just had another look and done "paper clip test" again and it has now thrown up 73.

Have checked both electrical connecters to MAF so will dig a bit deeper.

[Lazydocker]

Sounds like you may have disturbed a HT lead by accident 

[Marks DTM Calib]

Check all vac pipes and breathers, make sure they are connected ok and there are no splits.

Check the brake servo pipe for damage or holes.

Ensure that the idle valve is inserted correctly.

If you can, use a piece of metal to blank the EGR valve off as a test.

Also ensure the lieks of teh plenum O rings are ok including the complex one on the breather bridge.

Also make sure you didn;t connect the auto box breather by mistake instead of the engine breather.

[amba]

Thanks Mark.

All pipes have been checked and appear to be sound...brake servo pipe is correctly placed and no splits.

Will take of the plenum again over the weekend and double check that nothing is trapped,but its sods law you do a job you have done dozens of times before,especially in the cold and you end up having to do it twice,even though I didn,t rush it.

Why would I be getting a stored code 73 which comes back even when cleared,despite mne not touch the MAF ? could it have sucked some carb cleaner the wrong way and messed up the mesh inside it?

[omegod]

Poss coil pack gone west, mine seems to do this anytime I have a root around leaving me chasing my tail for days ! I think they do it on purpose

[amba]

Would have expected,and from previous experience of a faulty dispack,car to run worse than at present.

Best description I can give is its like its missing just 1 cylinder,idle seems a bit low an is not effected by climate being switched on or off,where as previously it would drop to a stable 500/550 without climate and then revs jump ut to say 6oo/650 when engaged.Now has no effect and whilst it will still run its not a smooth power delivery .

[omega3000]

Would have expected,and from previous experience of a faulty dispack,car to run worse than at present.

Best description I can give is its like its missing just 1 cylinder,idle seems a bit low an is not effected by climate being switched on or off,where as previously it would drop to a stable 500/550 without climate and then revs jump ut to say 6oo/650 when engaged.Now has no effect and whilst it will still run its not a smooth power delivery .

Could be coil pack , had exact same problem that threw up no codes . Mine packed up after working on the car "strange" but the coil pack was on its last legs 

[Marks DTM Calib]

Thanks Mark.

All pipes have been checked and appear to be sound...brake servo pipe is correctly placed and no splits.

Will take of the plenum again over the weekend and double check that nothing is trapped,but its sods law you do a job you have done dozens of times before,especially in the cold and you end up having to do it twice,even though I didn,t rush it.

Why would I be getting a stored code 73 which comes back even when cleared,despite mne not touch the MAF ? could it have sucked some carb cleaner the wrong way and messed up the mesh inside it?

There's your further hint!

73 is a MAF low reading......because the ECU has determined that the reading from the MAF is lower than it should be given the engine rpm and throttle position.........this can be MAF (VERY rare on 2.5/3.0 V6) or as already stated, an air leak (e.g. unmetered air getting in!)

[Ken T]

During a recent plenum off, I managed to trap the throttle vac pipe and a cable under the plenum when refitting. The intakes didn't seal properly and she ran very rough. Funny how simple jobs often turn out to take hours....

Ken

[tidla]

During a recent plenum off, I managed to trap the throttle vac pipe and a cable under the plenum when refitting. The intakes didn't seal properly and she ran very rough. Funny how simple jobs often turn out to take hours....

Ken

as forest gump once said.. those in the trade have to cover such troubles , which why those not familiar with the motor charge a bit more than the resident experts.