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Mass air flow sensor bad??

fuzzbutt

fuzzbutt

New member
Diagnostic help! Bad MAFS???

We have a 1998 3800 automatic and it has a bad stutter/lurching at 2kRPM or under when constant throttle and under load (i.e. a hill of any sort). I've replaced the Throttle Position Sensor, fuel filter, PCV, checked air filter, changed plugs, etc. Can this be a symptom of a bad Mass Air Flow Sensor?? If so, I need to find the thread for replacing it. if not, then I'm outta ideas!

Thanks!
 


Re: Diagnostic help! Bad MAFS???

yes a MAF could cause symtoms like that as well as a vacuum leak, does the SES light come on or flash?
 
We have a 1998 3800 automatic naturally aspirated that lurches/chugs only when at 2000RPM or lower at steady throttle when under a load (i.e. any hill). I've replaced the Throttle Position Sensor, fuel filter, plugs, PCV, air filter but to no avail. Can this be a MAFS? If so, where can I find a thread to replace it? If not, any ideas??

Help!

Thanks!
 
Re: Diagnostic help! Bad MAFS???

No lights come one and I've checked for any codes but nothing has shown. Can't determine any air leaks by spraying WD40 around most intake tracts, etc. so I'm thinking MAFS unless another good option is available. How much is a MAFS and how long will it take to replace? any special tools (these stupid Torx screws suck- most tool dept.'s have the Torx screwdrivers but not with the little stud in the middle!). Any threads for replacing the MAFS? I can't find the search option here.

Thank you.
 
Re: Diagnostic help! Bad MAFS???

fuzzbutt said:
No lights come one and I've checked for any codes but nothing has shown. Can't determine any air leaks by spraying WD40 around most intake tracts, etc. so I'm thinking MAFS unless another good option is available. How much is a MAFS and how long will it take to replace? any special tools (these stupid Torx screws suck- most tool dept.'s have the Torx screwdrivers but not with the little stud in the middle!). Any threads for replacing the MAFS? I can't find the search option here

Thank you.
Click to expand...

Those are called security torx screws, Harborfreight has a set of drivers for $5.00
 


Sounds similar to the problem I'm having with my RWD L36. If I've been at a cruise and drop it into neutral I will stall. If I "push-start" by going back into 4th or something, the car'll restart and be just fine until I do it again. Downshifting until I'm at the bottom of 2nd will keep the car from stalling. I've done the fuel filter and air filter. I'm throwing no codes and have none in memory. Any ideas?
 
Oops, sorry for double posting- my bad. Okay, so I'm not convinced it's a MAFS, as most of the other threads with bad MAFS had symptoms like engine dying, rough idle, etc.

No SES lights, no codes, nothing!

This is only one specific issue, when the car is under load at or under 2000 RPM ONLY. It lurches and stutters. Could this perchance be a transmission problem? Searching or slipping for the right gear? It doesn't feel or sound like a slipping gear- no change in RPM, no noise from the tranny, etc. Since it doesn't happen at 2K RPM on the flats, no load, then why would it be a fuel or air issue? Nothing is different at 2K RPM except under load, right? So, what else could it be? I'm so frustrated I could ****...

:O

3.8L naturally aspirated automatic SE, 111K miles
 
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