Possible throttle body problem on 4200?

[Andy4200]

Just wondering if this is normal, hoping to get some opinions please.
It's a manual gearbox by the way.

1. Idle speed seems high once warm, currently idles at around 1100rpm.
2. Very gentle blip of the throttle when stationary gives a sort of stumble. A bigger blip and it's fine.
3. The car drives fine but I find when pulling away you feel the bite point and feed in a little more power, it then seems to drop the revs so you almost have to overcompensate. This almost seems like point 2 above, just showing itself whilst moving, not stationary.

I wondering if the throttle body is dirty, therefore holding the butterfly open = higher idle speed and stumble issues.
Maybe I need to remove it, clean it and do a re-set?
No fault codes present.
Not sure what others think.
Thanks,
Andy.

 

[Zep]

It sounds like a air leak after the TB to me.

 

[Andy4200]

Good idea, that could be a possibility. I guess a leak wouldn't show a fault code.

 

[FIFTY]

Agree with Zep it sounds like a vacuum leak post MAF sensor

I have had it happen on the maser and my old BMW it causes some very strange behaviour.

 

[Andy4200]

I shall try and have a look later today.

Out of interest, what does yours idle at when warm?

 

[RJ237]

Many scanners will allow real time reading of fuel trims. A vacuum leak will cause high positive long term fuel trims,. Over 15 is significant, but a CEL will not be displayed until it reaches around 25.

 

[Andy4200]

That's really interesting, thanks. My scanner does real time reading so that could also help identify the issue.

I only posted the query a few hours ago and I've already got plenty of things to check, thanks everyone.

 

[Andy4200]

Results:
Visual check of hoses and connections and it all looks OK.
Live data LT fuel trims = -3.1 and -2.3
I guess that is OK then and possibly means no vacuum leak.

Idle revs on scanner approx 1000rpm.
Interestingly the TPS = 3.5% at idle. Maybe that should be lower?

Hmmmm

 

[GroovyBoovy]

Results:
Visual check of hoses and connections and it all looks OK.
Live data LT fuel trims = -3.1 and -2.3
I guess that is OK then and possibly means no vacuum leak.

Idle revs on scanner approx 1000rpm.
Interestingly the TPS = 3.5% at idle. Maybe that should be lower?

Hmmmm

Your idle speed look correct to me.

 

[RJ237]

Great fuel trims. Cleaning the throttle body and butterfly would be a good next step, and cleaning the mafs with the approved solvent while you have it apart may help. The flow sensor is actually inside the tunnel, the wire assmbly on the surface is the inlet air temp. sensor.

 

[Andy4200]

OK, so it looks like idle speed is OK. Just thought it might be lower. I guess with 8 cylinders and 32 valves it just sounds very busy!

Throttle body clean next on the agenda.
Thanks again for your thoughts.

 

[Mr S]

I have a spare working TB if you want to borrow it to test at any stage. Drop me a PM.

 

[rs48635]

I have a spare working TB if you want to borrow it to test at any stage. Drop me a PM.

Does it fit my 3200?

 

[Andy4200]

Thanks for the offer Mr S, I will bear it in mind, assuming it doesn't end up on a 3200

I'll try and give it a clean up at the weekend and see what's what.