P0101 Problem

My car is a 1996 Blazer, 105k, recently tuned. I had the service engine light come on so I took it to Shucks and it came back with a P0101 error. Also noticed while driving that the rpms tend to jump up and down and it also feels sluggish (which just happened to day). It is really fine at any low speeds and accelerates fine, but I noticed it happening much more at higher speeds. For awhile now (month) there has been a rattling noise on start up and around 1200-1500 rpms (in different gears) that seems to be coming from near under the driver. Any info is helpful.

Welcome to AF. A P0101 is a Mass Air Flow Sensor problem. Check and make sure your MAF sensor has a good connection to is harness. If that checks out alright, then my next suggestion would be to take off the sensor and spray brake cleaner through it or electrical cleaner to get it as clean as possible. Clear the codes re-install and see if that solves it. IF it doesn't then the next only option would be to replace the MAF sensor.

Would the mass airflow sensor cause the performance related problems?

Absolutely.

Drove it around today and didn't really notice any issues other than sometime under hard acceleration it would kinda lag down. Also right when starting the car up, there is a louder rattling noise behind the engine, but once warmed up it goes away.

When it's cool, get under the truck and hit the catalytic converter with your fist. Do you hear rattling?

Oh forgot to mention that I pulled the plugs on the Mass Air Flow sensor and then plugged it in again with no service engine light coming on (it was deleted or reset when I used the diagnostic thing last night). Tonight I am going to clean out the MAF and also I will check the cat and get back to you.

Thanks for the help so far trying to diagnose the problems. I should take some basic mechanic class or something (it would probably end up saving me some money in the future).

Check fuel pressure and leakdown. I've had several throw P0101 due to low fuel pressure. I'm not saying that's the problem with yours, but it's cheap, easy and quick to check it.

Check fuel pressure and leakdown. I've had several throw P0101 due to low fuel pressure. I'm not saying that's the problem with yours, but it's cheap, easy and quick to check it.

How do I check the fuel pressure and leakdown?

Connect tester to the service port on the fuel pressure line at rear of intake manifold, driver side near the distributor. Ignition on, engine off, fuel pump running, pressure must be 60psi to 66psi. Pressure must remain above 55psi for 3 to 5 minutes after fuel pump shuts off.

Connect tester to the service port on the fuel pressure line at rear of intake manifold, driver side near the distributor. Ignition on, engine off, fuel pump running, pressure must be 60psi to 66psi. Pressure must remain above 55psi for 3 to 5 minutes after fuel pump shuts off.
What kind of tester do I use and where can I get one? And how to I go about cleaning the mass air flow sensor. I took it out and have it now. #Figured out how to clean the MAF and did so#

So I checked the cat and did notice that when I hit it with a rubber mallet that there was some rattling noises coming from in side it. Sounded like something shaking around and then coming to rest about a sec after I hit it. Should I take this in to a mechanic or what?

Noise from inside the cat indicates a overheated cat. Basiclly, the cat has melted inside and needs to be replaced. This causes a restriction in the exhaust and causes performance problems. The cat usually overheats as a result of to much unburnt fuel getting to it. A MAF sensor can contribute to this problem if its causing it to run rich, but may not always be the problem. As oldmaster mentioned, for sure check and verify fuel pressure/leakdown.

What kind of tester do I use and where can I get one?


http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92699

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92699

$!2.99 That's amazing. I'll see if the Harbor freight in my area has one. If so, I'll buy it and check this out.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92699

O.K. guys You ain't gonna believe this. I found one of these tester kits at my local Harbor Freight store ON SALE for $10.00 USD (normally $12.99). The kit has 3 different hoses and other connectors. The gage itself is completely encased in rubber for shock absorbtion.

I just brought it home and have not tried it out on a vehicle yet, but my preliminary impression is WOW. Even if the gage turns out to be garbage, the hoses and connectors are worth the $10.

Sorry for trashing your thread fox3r, but this is good info.