Intake gunk cleaning
 

Hoped I could call on some collective wisdom here.... Have a V70 SE Manual 2.4D 163hp with a sticking accelerator.
Had some minor stalling issues (usually at the end of the road after a cold start) @ around 100,000 miles and my excellent independent mechanic had the egr assembly apart and cleaned out. I’ve never seen anyone as filthy in my life when I collected it! But problem resolved.
Now approaching 200k and the same problem returned, and was seemingly cured by cleaning the throttle valve (the part on the front of the engine that looks like it blends the fresh charge air with the recirculated exhaust). Cleaned it in situ, physically where I could, and also by running the engine and spraying carb/egr cleaner in the inlet. In addition I have filled the last few tanks with BP and one with diesel purge, in case you believe in that sort of thing (by which you might guess I’m a ‘bit’ sceptical).
So the stalling is cured (and mpg improved back to previous levels), but the net effect seems to have carried thick liquid tar further into the inlet and as a result the response to the accelerator is decidedly sticky, and at the weekend drove home 50 miles where the revs wouldn’t drop below about 1600 rpm.
Have just fed the engine my last 1/4 can of egr cleaner while on tickover, making sure it went all around the inlet, and the problem cured (good throttle response and normal tickover rpm), but only for 20 miles or so before sticky response and high idle rpm returned.
Before I pull it all to pieces, I wondered if my theory that using spray cleaners and additives simply softens the residue and pulls it through the system until the crap meets an obstruction on a sharp bend (throttle body) where it then deposits itself?
In an ideal world I would love to drop something in the tank that would make it all shiny and new inside, restore performance and mpg, improve combustion, reduce emissions and solve the middle east problem. So I guess I’m asking if anyone can genuinely vouch for such a product?
Or should I just get the rubber gloves out and dive in there?
All comments gratefully received.....

Just to be really clear here, you have a diesel?
The throttle does NOT govern the engine speed, only the volume of diesel injected does that and that is based upon load as determined by the pedal position (and a billion other inputs). The throttle plate is only there to ensure a prompt shut down when you kill he ignition and to prevent the engine burning its own engine oil in the event of a massive PCV system failure.
It doesn’t do the same job as it does in a petrol engine...

If you’ve unusual idling, you need VIDA on the job.

P.S. the throttle pedal is all electric so regardless as to how gunked any engine component was, the pedal stiffness is defined by the return spring. There is no mechanical connection between the pedal and any component apart from the floor and possibly some floor mats.

RECAP
Your initial 100K generated the need for EGR disassembly and thorough cleaning.

The second 100K brought out the solvents and sprays.
Hmmm....

Thank you Kira
 

I was hoping for some collective wisdom, not a severe edit of what I wrote, but omitting all detail that might inform someone who wanted to actually be helpful.

I know from the state of the mechanic who stripped it out first time, that I would happily not subject myself or anyone else to that, if there was a fair chance of a better way succeeding....

Hi can you please tell us the year of the car,
Thanks Dave

Hi
Sorry, it's a 2007 P2, last of the old shape. There seems to be confusion over the engine, I'm sure this is the derated D5 (185bhp), but badged as a 2.4D (so 163bhp).

My apologies for being short of words or sounding snotty. Not my intention.

People have posted on this before, some with pictures, and given that you reported how miserably dirty the job was your first time 'round, it seemed inevitable that the same dirty job was needed again.

My thoughts-which I did not explain-were of you being taken in by promises printed on cans. Believe me, I hold "mechanics-in-a-can" in low esteem and mock them, not you. Cheers

I once won a significant bet over the failed promises of a “decoke tin”. Given I was going to take the head off anyway, I purchased the tin and used it as instructed, and then took the head off. I was holding an inlet valve in a drill and whizzing it up with a scraper against it to knock the carbon off. The tin didn’t do anything and I got the ‘told you so’ rights with the chap in the parts store. (I didn’t pay for the tin or most of the h ad gasket set either....)

There is generally very rarely a substitute for elbow grease.
VIDA will help you through your sticky and erratic idle. For everything else, there’s clean it properly.

"So I guess I’m asking if anyone can genuinely vouch for such a product?"

I share your scepticism.

Just need to plot out a scheme of work as car is in daily use so need to tackle recirc. system 1 element at a time.

Quick question on the turbo, just wondered what state the exhaust side of that gets, and what's the best method of cleaning it if necessary?

Thanks

Manual Vs Youtube
 

Its definitely worth having a cleanout.. you can find lots of stuff on youtube where some co is introducing its magic cleaning agent, i saw one where the guy was revving the engine while a whole load of black stuff was coming out the back end with associated large black ring on the floor, but you have to wonder what effect of all that gunk and cleaning agent is doing when it heads for the dpf, and cat etc, personally i don't think you can beat the manual take it apart approach..takes more time perhaps, a bit like coal mining..it should be on the service schedule but i suspect it isnt..

The throttle body's are known to strip the gears when the gunk builds up to excess.. Was trying to find some pics, (attached) of how the throttle body looked when i had mine apart at around 90k.. its also not too hard to remove and clean out the big rubber inlet pipe, i found on mine probably 5-6mm thick of soot inside.. carb cleaner works well, but wear gloves as i suspect the soot isnt too healthy (also attached some pics of the tools needed to do the job !) oh and the gasket on the D5 Euro4 throttle body