99 Blazer LT Multiple Codes

[vando002]

I have a 99 Blazer LT 4WD 160k. My wife was driving it home from work and it started bucking and having a really hard time going more than 30 mph. Even shifting through the gears manually, the truck still doesn't have power and seems like it's having a horrible shifting problem. Barely making it home, she popped the hood and I checked it out. It smelled awful, like fluid was burning. I haven't gotten under it yet to check it out, but I thought I saw some tranny fluid on the transmission. I noticed the Check Engine Light was on (has been for awhile, my fault for not checking it sooner) and I plugged in the code reader. To my amazement, there were 5 codes.

P0101 - MAF or VAF CKT Range/Perf
P0147 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 3)
P0300 - Random/Multiple Cylinder Misfire Detected
P0446 - EVAP Emission Control System Vent Circuit Malfunction
P0452 - EVAP Emission Control System Pressure Sensor Low

Has anyone had any issues like this before? The truck barely drives at all, smell like fluid is burning, recently had a tune up (plugs, wires, cap, rotor), never had a problem like this before. Any guidance would be great. I'm don't have a lot of equipment to check pressures and am really not very familiar with electrical systems. Please provide a little bit of guidance. If it's a really complicated issue, I may have to bring it to the mechanic. I don't have a lot of time either with working so much. Any help would be great.

Thank you!

Adam

[jd-autotech]

my best stab would be a vacuum leak or evap system leak maybe clear codes and see which ones come back and focus on those codes if the light was on you dont know which are associated with this problem

[MT-2500]

Originally Posted by vando002

I have a 99 Blazer LT 4WD 160k. My wife was driving it home from work and it started bucking and having a really hard time going more than 30 mph. Even shifting through the gears manually, the truck still doesn't have power and seems like it's having a horrible shifting problem. Barely making it home, she popped the hood and I checked it out. It smelled awful, like fluid was burning. I haven't gotten under it yet to check it out, but I thought I saw some tranny fluid on the transmission. I noticed the Check Engine Light was on (has been for awhile, my fault for not checking it sooner) and I plugged in the code reader. To my amazement, there were 5 codes.

P0101 - MAF or VAF CKT Range/Perf
P0147 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 3)
P0300 - Random/Multiple Cylinder Misfire Detected
P0446 - EVAP Emission Control System Vent Circuit Malfunction
P0452 - EVAP Emission Control System Pressure Sensor Low

Has anyone had any issues like this before? The truck barely drives at all, smell like fluid is burning, recently had a tune up (plugs, wires, cap, rotor), never had a problem like this before. Any guidance would be great. I'm don't have a lot of equipment to check pressures and am really not very familiar with electrical systems. Please provide a little bit of guidance. If it's a really complicated issue, I may have to bring it to the mechanic. I don't have a lot of time either with working so much. Any help would be great.

Thank you!

Adam

I am sure other people have had them problems.

Find that fluid smell.
Check all fluids for being low or leaking.

As said clear codes and see what one comes back first.
How many miles and what engine?
When was last good tune up with AC delco parts?

Always check fuel pressure and for good hot blue spark to all plugs.

Any cold air intake stuff?
Air intake in good shape?
Unplug MAF sensor and see if it makes any difference.

[Rick Norwood]

I had a similar issue with a 2001 4wd Blazer. There was a LIST of issues, many of which you are seeing in the codes (MAF sensor, O2 sensors etc.). The biggest surprize on the list was the distributor itself. There was over a half inch of wobble in the distributor shaft. The wobble was so bad that it snapped the tip off of the rotor. This caused a ton of raw fuel to be pushed out into the exhaust manifolds. My exhaust pipe turned cherry red and melted the O2 sensor along with the catalytic converters. The smell COULD be the result of the unburned gasoline in the exhaust pipe and the excessive heat. If it will start, look underneath while it is running and see if your exhaust pipes are turning red.

FYI, we had to replace the distributor, MAF sensor, O2 sensors, Catalytic converters, and sections of Exhaust pipe that also melted. It cost us $1600.00 USD to drive it home.

It is a very simple and free check, take off the distributor cap and see how much side to side play is in the distributor shaft. If you can move the shaft more than a few thousandths of an inch, you may have excessive play.

[vando002]

Originally Posted by Rick Norwood

I had a similar issue with a 2001 4wd Blazer. There was a LIST of issues, many of which you are seeing in the codes (MAF sensor, O2 sensors etc.). The biggest surprize on the list was the distributor itself. There was over a half inch of wobble in the distributor shaft. The wobble was so bad that it snapped the tip off of the rotor. This caused a ton of raw fuel to be pushed out into the exhaust manifolds. My exhaust pipe turned cherry red and melted the O2 sensor along with the catalytic converters. The smell COULD be the result of the unburned gasoline in the exhaust pipe and the excessive heat. If it will start, look underneath while it is running and see if your exhaust pipes are turning red.

FYI, we had to replace the distributor, MAF sensor, O2 sensors, Catalytic converters, and sections of Exhaust pipe that also melted. It cost us $1600.00 USD to drive it home.

It is a very simple and free check, take off the distributor cap and see how much side to side play is in the distributor shaft. If you can move the shaft more than a few thousandths of an inch, you may have excessive play.

Thank you for your responses. I took a look at it last night, I replaced the fuel filter, which I hadn't done in a long time and I replaced the air filter. I took the intake off and cleaned out the throttle body with sea foam while the truck was running (tons of smoke!). Put everything back together and took it for a drive. Still the same issue, awful acceleration and real issues shifting into each gear. It just wants to wind out like I'm driving a manual vehicle. I unplugged both sensors that are on the intake (the MAF and another sensor) and it seemed to do much better for a little bit. Then it went back to the same issue. Then it got worse. I was at a stop sign at a busy road, I decided not to pull out onto that road, instead I backed up into someone's driveway and turned around. Good thing I did this, when I went to accelerate, there was absolutely nothing. Pedal to the floor and I wasn't going any faster than coasting. So I drove it all the way back home letting the vehicle drive itself basically. I don't think I even hit 5mph (luckily no hills in Illinois). When I hit the gas, nothing happened at all. It seemed like it was going to stall out when I hit the gas. No acceleration at all. So I crawled all the way back home and remembered to check my exhaust pipe. Sure enough, cherry red just after the catalytic converter. Incredible. So Rick, are these any of the driving symptoms you had when your distributor went bad? I haven't checked it yet, I will tonight though.

Of course after all of this the Trouble Codes came back and the codes were the following:

P0101 (twice) - I'm guessing because it was unplugged
P0102
P0106
P0108
P0147

I didn't have time this morning to write out what each one is but I believe 102 is also MAF, I think 106 & 108 were the MAP sensor, and of course P0147 is for the O2 sensor.

MT---160k, 4.3L Engine, Autolite parts used for tuneup, I don't have cold air intake and the air intake is fine. I did unplug the MAF and it helped for a very short time.

Any help would be great with this. Thanks.

[MT-2500]

101 and 102 are MAF sensor codes
106 and 108 are Map sensor codes.

Could be two different problems.
Sensors or wiring to them.

You may need a scanner to see what the sensor readings are on computer.

[Rick Norwood]

My Daughter was driving the truck when it went south. According to her, it was fine all the way to her school and died in the turn lane to the parking lot. She actually had to get other drivers in the turn lane to push her out of the way. So no, we did not experience the gradual symptoms, it was on and off.

Again, the cherry red exhaust pipes is unburned fuel dumping into the exhaust system, which in my mind says the ignition is not taking place in the cylinders.

One other thing we also had on this same truck but at a different time was the distributor cap shorted out between number 1 and number 2 posts. This also caused a huge amout of codes, and a lot of the syptoms that you have described. This ended up to be a new cap and wires. Fundamentally, My opinion is that your problem is in your ignition system.

Hopes this helps.

[blazes9395]

While this problem can easily be a few things, like the distributor, like Rick mentioned, if your scanner can view real time data, take a look and see what the MAF sensor is reading. The MAF is an important part of the engine management system. If its not reading properly, or just plain not working, it can make an the PCM go crazy trying to compensate - you need to get that fixed first. Unpluging the MAF and getting a temporary better running engine defiently sounds like MAF is bad. P0147, and P0300 are most likely a result of it having to much unburnt gas going through the engine. Getting a cherry red pipe and cat, is basiclly burning the cat, eventually melting it internally, so I wouldn't drive it like that, or you'll be replaceing that cat soon.

[vando002]

Sorry it's been a long time since responding to this but I haven't had much time at all to look at this truck. I took a few minutes today to look at it. My Dad mentioned that it sounded like a plugged cat and to drill a small hole in front of the cat to see if that helped. Well, I drilled two small holes just before the cat and took it for a drive. It helped a lot, but was still having acceleration issues. So I went back to the house and drilled two more holes and before leaving I went a couple drill bit sizes higher to make the holes larger. Well that truck runs a little louder now, but now it has no problems getting up to 60+ MPH. I couldn't believe it. It runs like a charm and shifts great. The acceleration isn't 100% but once a put a new cat in, I should be good to go!! Thanks for your help guys!!

[MT-2500]

Originally Posted by vando002

Sorry it's been a long time since responding to this but I haven't had much time at all to look at this truck. I took a few minutes today to look at it. My Dad mentioned that it sounded like a plugged cat and to drill a small hole in front of the cat to see if that helped. Well, I drilled two small holes just before the cat and took it for a drive. It helped a lot, but was still having acceleration issues. So I went back to the house and drilled two more holes and before leaving I went a couple drill bit sizes higher to make the holes larger. Well that truck runs a little louder now, but now it has no problems getting up to 60+ MPH. I couldn't believe it. It runs like a charm and shifts great. The acceleration isn't 100% but once a put a new cat in, I should be good to go!! Thanks for your help guys!!

You are welcome.

After you replace the cat clear codes and recheck everything.
There may be a engine running problem that pliged up cat.

After code clear watch for any codes coming back and post back code.
Good luck

[b1lk1]

Catalytic converters don't usually fail without underlying issues with the engine.

[vando002]

How hard would it be to change the catalytic convertor myself with a direct fit application?

[REALOLDS]

I have a muffler shop and can install a universal (which is the same converter body without ends) for $175 unfortunately I'm in Kentucky. If you can get it done for $250 or less its probably not worth the fight of doing it yourself unless you hve a torch to heat the bolts.

[MT-2500]

Originally Posted by vando002

How hard would it be to change the catalytic convertor myself with a direct fit application?

Not much more than changing muffler.

A direct fit usually just bolts on.
And be sure to find out what caused it to fail.
Fix all engine running problems/codes or you will be repacing cat again.
And pitch them Auto light plugs and get some good AC delco plugs
Good Luck