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Virtual Wrench
Virtual Wrench, Chevy Mechanic
Category: Chevy
Satisfied Customers: 14620
Experience:  35 years Master Mechanic
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98 chevy s10 blazer: trouble codes..p0171..intake manifold gaskets

Customer Question

I have a 98 chevy s10 blazer 4.3 trouble codes p0171, p0174 & p0102. I was told to replace intake manifold gaskets, did so I again popped the same codes! relaced pcv and checked all vacuum lines, replaced fuel filter, plugs, wires cap & rotor. Cleaned MAF. Battery is borderline ? Haven't checked fuel pressure. What do you suggest?
Submitted: 10 years ago.
Category: Chevy
Expert:  Virtual Wrench replied 10 years ago.

Here is the read on these codes 0171 is for the MAF sensor and the other 2 could be from the MAF being bad. You really need a scan tool to check the MAF, but if you feel lucky, you can just replace it.

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If you have further questions on this, please feel free to reply.

Thanks for asking!

V W

Customer: replied 10 years ago.
Reply to Virtual Wrench's Post: If the battery is questionable could this also affect codes in the system and is fuel pressure a possibility or not? Can the MAF be cleaned and if so how, should battery be disconnected while doing cleaning? Are MAF's expensive?
Expert:  Virtual Wrench replied 10 years ago.

If the battery is good enough to start it, it wont affect it. Do NOT use cleaner on the MAF sensor, because it can ruin it. They run around $100 so thats why it's best to have it on a scanner to test it while it's running.

Customer: replied 10 years ago.
What type of scan tool do I need to check MAF?
Expert:  Virtual Wrench replied 10 years ago.
You can use a Tech 1 or 2 type scanner
Customer: replied 10 years ago.
If the vehicle has already been scanned 4 times and cleared, isn't that the same as what your asking me to do?
Expert:  Virtual Wrench replied 10 years ago.

No, there is a difference in scanners, the one you are relating to is a code reader, and can not be used to obtain "live" readings like the Tech 1 or 2 scanner. These are usually only bought by a professional, because they cost around $3000

 

 

Customer: replied 10 years ago.
OK, yes that was done and showed the 3 codes I mentioned. So I should feel confident then to replace MAF, correct?
Expert:  Virtual Wrench replied 10 years ago.

Here is the complete testing procedure, i wouldnt replace it unless you check all of this out.

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Virtual Wrench and 6 other Chevy Specialists are ready to help you
Customer: replied 10 years ago.
Relist: I prefer a second opinion.
Expert:  Virtual Wrench replied 10 years ago.
What else can i do for you?
Customer: replied 10 years ago.
Can I check for vacuum leaks by spraying carb cleaner around the intake gasket, MAF, EGR and all other vacuum ares? If so should it increase rpm if I find a vacuum leak?
Expert:  Virtual Wrench replied 10 years ago.

I really want to help ya out, but these darn sensors are so hard to test.

 

Expert:  Virtual Wrench replied 10 years ago.

Sorry, looks like we posted at the same time.

Yes you can check for vacuum leaks by spraying cleaner around the gaskets and if the rpm goes up it indicates a vac leak.Be sure to check the egr valve also.

Expert:  Virtual Wrench replied 10 years ago.

Keep me posted how it goes, and i will help you as much as possible, no problem.

Customer: replied 10 years ago.
Is that a yes or no to my last question?
Expert:  Virtual Wrench replied 10 years ago.
That would be yes :-)
Customer: replied 10 years ago.
One other thing If I disconnect the battery to clear codes and they don't clear then what should I do?
Expert:  Virtual Wrench replied 10 years ago.
Usually when you do the disconnect, it clears the memory, until it picks up an out of range signal from one of the sensors, then triggers the light to come on again.
Customer: replied 10 years ago.
OK, I can't get the light off now. How long should I leave the battery disconnected?
Expert:  Virtual Wrench replied 10 years ago.

If you disconnect the cables and hold them together for 30 seconds or so, it should reset.

You can also remove the ECM fuse.

Customer: replied 10 years ago.
OK, Thanks
Expert:  Virtual Wrench replied 10 years ago.

Your very welcome.

Best of luck my friend!