Throttle tip-in issue/stumble (3.0 5-speed)

[Masospaghetti]

Originally Posted by 80stech

You can try rapping on the MAF with your knuckles while the engine is running to see if there is a stumble. (doesn't rule out a bad MAF though) You can also try disconnecting the MAF (key off) and try taking it for a drive. (doesn't mean for sure the problem is the MAF but gives some direction) The throttle pedal pots giving offset or opposing signals is normal. Are you really really sure there are no codes? How old are the spark plugs?

and yep, idle air control might be worth a try.

You were right. there was no CEL and I thought there were codes, but sure enough I found a few. I don't think they are relevant here but the translation is pretty tough.


RLS-DS2 looks like the rain sensor which sure enough does not work.
LCM_IV is the light control module?
The IKI EEPROM error is probably because the gage cluster was previously replaced.

[80stech]

I was thinking more DME codes but it wouldn't hurt to clear all. Have you tried clearing DME adaptations ?

[EODguy]

I think 80stech has you on the right track. Once cleared see what comes back and I'd do live data to see if something shows up without causing a code if none reappear.

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[Masospaghetti]

Checked DME codes and found Code 90, "TEG_UP_1" and Code 91, "TEG_UP_2". Both have error frequency of 0 with message "Error currently not present".


I cleaned my IAC, it had some soot and grime in there, replaced the air intake elbow at the same time. Feels the same though. Still stumbles.

[80stech]

Did you reset adaptations? Can you get code descriptions? even in German, you can maybe use google translate or post the German, I am fairly fluent.

[Masospaghetti]

Here are the screen readouts from the DME error codes.


I just reset all of the adaptations but haven't tried it yet.

[80stech]

Doing a quick search on google for you shows that codes 90 and 91 are fuel control and people have found vacuum leaks the cause.

[Masospaghetti]

Originally Posted by 80stech

Doing a quick search on google for you shows that codes 90 and 91 are fuel control and people have found vacuum leaks the cause.

Honestly that would 100% explain it. I did a smoke check and found nothing but that was adding smoke ahead of the throttle body. I'll try smoking it out somehow thru the intake manifold and check for leaks.

[Masospaghetti]

Did another smoke check, this time through the "y" joint going to the brake booster. No trace of smoke, unfortunately.


I'm getting close to biting the bullet and trying a new VDO/Continental MAF. From the other forums I see a lot of folks warning not to use any aftermarket brands. A bit spendy but not sure what else to try.

[80stech]

I've never done a smoke test so maybe someone else can chime in on that. A smoke test
might be useful to help find a vacuum leak but doesn't eliminate it as a problem.
It takes a little "finesse" to center the IAC motor back into the intake seal (good to replace that as well) so hopefully you didn't add a vacuum leak there, and hopefully you didn't use carb cleaner on the IAC.