Question about Cars & Trucks

2 Answers

My Hummer want run but 40mph and on the scanner it shows mass airflow sensor and multiple miss fires replaced mass airflow and still showing same codes

Posted by on


2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Cars & Trucks Master
  • 5,438 Answers

Need more information. How many miles on vehicle? Ever changed plugs? Ever smell funny? Blocked exhaust/bad catalytic converter can cause these issues, Burned plug wires, fouled plugs, bad O2 sensors, bad coolant temp sensor, restricted intake path (dirty air filter), bad fuel filter (rare). If these tests are beyond your skill set, time for pro diagnostics I'm afraid. Might save $ all in all.

Posted on May 17, 2014

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert who has answered 20 or more questions within one hour.


    An expert who has answered 20 questions.

  • Expert
  • 110 Answers

Crank sensor would be my next bet. 40 mph is safety mode to not damage the engine. i.e get home mode.

Posted on May 17, 2014


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

  • 2984 Answers


Very easy for the Mass Air Flow is in the duct between the throttle body and the air filter box. Just unclamp the tube and remove the old and replace with the new.


On your pack....I need the engine size.

Posted on Mar 26, 2009

  • 38 Answers

SOURCE: Bmw E46 318i touring. fail code 171

171 check, fuel supply system short circuit to b+

Posted on Jul 11, 2009

  • 398 Answers

SOURCE: 2000 hyundai sonata.. P0300, P0110 and P0102 codes..

Higher octane gas 93 with some good octane boost in the black can at autozone cost about 7 dollars or a bottle of 104 octane boost. Change the fuel filter. Probably only one coil pack is bad. The OBDII reader should tell you which one was a misfire.

Posted on Jul 15, 2009

  • 221 Answers

SOURCE: p1320 trouble code plus

The P1320 code is essentially a coil primary voltage problem. This is traceable using a labscope or accurate DVOM and perhaps you can isolate one or two coils that still work but are close to failure...but there is a nissan service message recommending replacement of ALL coils with updated/improved models to prevent this type of failure. TCS/SLIP is traction control. Most likely you have a speed sensor issue. Be aware, some vehicles can falsely illuminate TCS because of low tire pressure in a single wheel.

Posted on Sep 09, 2009

Testimonial: "thanks needed a point in the right direction"

  • 1214 Answers

SOURCE: 2003 Tahoe Running rough, Idle irratic, Ck engine

Yes, replace the MAF, then check if the lean condition goes away. It should.

MAF's are sensitive to cleaning. Sometimes it works, other times it doesn't.

Posted on Dec 11, 2009

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer


On all vehicles in the 1980's car makers started using computer controlled fuel injection systems and these systems have numerous sensors . These sensors give information to the computer for fuel control. Some of these sensors are the coolant temp. , mass airflow, oxygen sensors, if one of these sensor is reporting wrong information to the engine computer it could cause the symptoms you are experiencing. Along with vacuum leaks, plugged catalytic converters, miss firing spark plugs . Most usually a flashing check engine light will accompany a miss fire. These sensors degrade over time and miles, and it helps to have a diagnostic scan tool to check the sensors outputs to the engine computer. Fuel trims can also be viewed on a scan tool , these short term and long term fuel trims show how much fuel is added or subtracted, positive numbers = adding fuel negative numbers = taking fuel away . So what I'm trying to say here is that these are complex systems and sometimes you need to take them to someone who has the tools and knowledge to fix them !

Jul 23, 2014 | 2001 Ford Windstar

1 Answer


Doubt its tranny more likely a mass airflow sensor or crank position sensor put vehicle on active scan tool while running watch the mass air sensor readout if it stops on a certain reading replace the sensor. Could also be a stuck egr pindle old engine codes would show this scan vehicle codes and get back to me

Apr 11, 2014 | 1996 Dodge Caravan

1 Answer

I have a 2003 olds alero 2.2 ecotec engine,when first cranked the idle is fine,then die down the code shows p0300 rapid miss fires ,changed the plugs,switched out module,coil, it stiil does this,while its...

p0300 random misfire can becaused by a few different thing's - low fuel pressure or flow ,weak fuel pump, clogged fuel filter , clogged injectors , vacuum leaks , incorrect sensor input to PCM - mass airflow sensor or MAP sensor , TPS - throttle postion sensor , Hooking up a professional or factory scanner an viewing engine sensor data should be the first step in the diagnostic process , before ever replacing any parts . What are the fuel trims at ? Adding or taking away fuel ,O2 sensors switching normally ?
016 Engine Misfire Misfire Scan Data

Feb 23, 2018 | Cars & Trucks

1 Answer

1990 mustang shuts off with mass airflow sensor plugged in

try another mass airflow sensor. I know they're expensive to buy....but if you could find another good used one to try....

good luck

Jan 09, 2013 | 1990 Ford Mustang

1 Answer

I have a 2008 pontiac torrent showing a po171 code as well as a po300 miss fire

p0300 is a random multiple misfire, could just need a tune up.
you should have the mass airflow sensor cleaned, the p0171 is showing incorrect fuel mixture, best to have the vehicle scanned at a shop so the exact issue can be pinpointed

Oct 11, 2012 | 2006 Pontiac Torrent

1 Answer

2005 hyundai xg350 problem starting


Sep 12, 2012 | Hyundai XG350 Cars & Trucks

1 Answer

Check engine light

You first need to run an OBD1 fault code test of the engine control module(ECM), if nothing shows up as far as fault codes goes then you may have a defective MAF (mass airflow) sensor or TPS (throttle position sensor). You can buy the OBD1 system scanner you need on eBay for around $100.00

May 04, 2012 | 1990 Toyota 4Runner

1 Answer

Check engine light 1999 Pontiac 150,000 Mass air Flow code was posted on MT2500 Snapon scanner replaced the Censor now code for lean bank one shows ,replaced fuel filter checked Vacumn shows 20 what do...

replace the mass airflow sensor.. try used they normally will not need to be calibrated or programmed to the car. New ones cost more and are harder to get working. (and new ones cannot be returned.. used ones always work best for me..

Oct 27, 2011 | 1999 Pontiac Grand Prix

1 Answer

Code po100 & p0300 come up. then I clean throttle body with cleaner, then the van stops missing & run good & light go's out.

P0100 is mass airflow circuit, p0300 is multiple cylinder misfire. Faulty maf sensor is most likely the cause of the misfires.

Mar 11, 2011 | 1998 Chevrolet Astro

1 Answer

98 Jimmy has 5 codes (multiple misfire; egr; mass air flow; intake air temp; manifold pressure) Was dogging out on me and the other day it quit. Now it turns over but will not start. Checked and it is...

I would start with the Mass Airflow and EGR sensors first, because they can cause the misfire codes and the intake pressure and temp. Just because the air filter and hoses are clean and free flowing doesnt mean the computer can see that. If your Mass Airflow sensor died, as far as the computer is concerned, there is no air going into the engine.

Jul 28, 2009 | 1998 GMC Jimmy

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

71 people viewed this question

Ask a Question

Usually answered in minutes!

Top Cars & Trucks Experts


Level 3 Expert

80339 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

john h

Level 3 Expert

15190 Answers

Are you a Car and Truck Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides