I have a 2001 blazer 4.3 4X4. It's my only family car . I am married to a wonderful mother to our babes. please help us with this problem. we both have full time jobs but not much money.I bought a Acton to help with this VERY BIG PROBLEM, Any comments would be greatly appreciated. Thanks Larry R

 

You must meam P0174

That code is for "system too lean bank 2"

That means you have an air leak after your mass air filter (MAF). You will want to start by looking for the simple things like the intake tubing connections being loose, cracked.plenum, loose plenum bolts, maybe a cracked intake tube -they are like dryer ducting and can crack in the grooves. Look for any of the sensors that plug into it maybe came out leaving a hole to suck air through.

The MAF is that sensor just after the air filter, it measures the amount of air passing through it so the computer can determine how much fuel to inject. If the engine is sucking in air from elsewhere, then its measuring less air through it resulting in a lean run condition.

If everything is tight, you may wish to try cleaning the MAF sensor with some CRC Sensorkleen spray and a q-tip but be very careful not to damage the wire inside, just be gentle with it. If the problem persists, you will want to replace the plenum gaskets. Those are all the gaskets that go in the plastic part between the aluminum intake, and the air filter.

It doesnt take much of a leak to trip the code off.

You can also help to find the leak with a spraycan of carbuerator cleaner or an unlit propane torch. With the engine running idle, spray the cleaner or torch around all the gasket surfaces, when the engine sucks in some propane through the spot that is leaking - your rpms will go up a little...

Try this out and let us know if you found anything.

 

2001 Chevy Blazer, 4x4 LT, 4.3 Vortec has no power. Cannot throttle it above 1500 rpm. It falls flat on it's face. I have replaced the MAP Sensor, MAF Sensor and connectors for both. Put in brand new AC Delco 41993 plugs and wires. New cap and rotor, new ignition module, new coil, new crank sensor. Motor still falls flat. I've had 2 people suggest that it might be a catalytic converter or my engine control computer. Went to the junkyard and pulled an engine control computer, same make and model and now the car won't even start. But with the old ECC at least the engine would start and idle. It seems like it gets worse as the car gets hotter. Took it to a Chevy dealership to have it put on a diagnostic machine but the only thing that came back was P108 and P300. Cleared the 108, MAP sensor fault. Still have a P300 which is multiple misfires. How do I flash the ECC to adapt to my car?

 

before you do anything else,check the fuel pressure with a actual fuel test kit. you can get a free one through autozones loan program
(leave a deductible which is refundable). use the test port behind the engine on right side. it'll have a black cap. disconnect the spark plug wire at the coil so it wont start. connect the fuel tester to the port,and turn the motor over for 5 secs or so. look at the gauge. It must be above ideally 60 psi+. If it bumps up to say 51 etc then pump is weak. if it does bump up past 60 leave it alone for 10 min and make sure it doesnt drop below 55ish.

if its the pump,replace it with ONLY a ac delco brand pump,none of the aftermarket stuff as it doesnt last in our blazers. they are a hit or a miss. You might wanna replace the fuel filter before the test to increase accuracy.

 

the 704 code cleared after i installed a new fuel pump & filter . then 1/2 tank latter WHAM BAM!! all hell broke lose

checked fuel presser at Schroeder valve got 61 solid lbs for about 5 min

 

Thanks for all suggestions. BUT it's still falls on it's face at 1400 rpm, purrs like a kitten at idle at 1400 rpm i would turn on the a/c the rpm drop and engine then runs rough. how do test if my cat is
plugged?? would it show as a code or not. there two black canisters on the intake one in front and one behind the throttle body, i have no idea what they are could this be part of the problem??

 

Have you tried pulling the throttle body and cleaning it really good? I had the same issue with loss of power and would stall when you turned the ac on in my wifes mustang and I cleaned the throttle body and haven't had a single issue since.

 

just the body or the plastic that mounts to the intake manifold

 

If you pull the intake tubing off and flip your tb blade with your finger I bet its really black and heavy with build up. The best way to get it really clean it to remove it from the motor and get a good tb cleaner and a tooth brush and spray the hell outta it and scrub it with the tooth brush till its clean. I can't see why it would hurt to do what you can in the manifold either. Then reinstall the same way it came off. Make sure you disconnect the battery before you start. When you put it back together your truck will have to do a relearn with the clean throttle body but it will do that itself nothing you have to do. I hope this helps and if not let us know.