Considering purchasing a 1996 GMC Yukon. Advice?

[steve_bier]

Hi there -

 

New to the forums, and was not sure where I could post this, so please go easy on me!

 

I'm considering purchasing a 1996 GMC Yukon. Body and interior are in decent shape, and the price is a near giveaway (under $1K).

 

The problem is that the car failed the NJ emissions inspection. The results are listed below:

 

Primary Emission Test Performed:OBD - FAIL

OBD SYSTEM - DIAGNOSTIC RESULTS

-Bulb Check: PASS

-OBD Connector: PASS

-MIL Command Status: FAIL

-Check Engine Light On: FAIL

-OBD Communications: PASS

-Overall Readiness Result: FAIL

OBD SYSTEM - READINESS STATUS

-Engine Misfire READY

-Catalytic Converters NOT READY

-A/C Refrigerant UNSUPPORTED

-Fuel System READY

-Heated Catalytic Converters UNSUPPORTED

-Oxygen Sensors NOT READY

-Comprehensive Component READY

-Evaporative System UNSUPPORTED

-Oxygen Sensors - Heaters READY

-Secondary Air Injection UNSUPPORTED

-EGR Systems NOT READY

OBD SYSTEM - DIAGNOSTIC TROUBLE CODES PRESENT:

-Total # of codes Present: 2

-Individual Codes Present: P0134, P0300

Secondary Emissions Test(s) Performed:

TEST RESULT:

Gas Cap PASS

Tampering PASS

Visible Smoke PASS

Liquid Leak PASS

Indicator Light FAIL

Misc. Emissions PASS

From the owner's ad:

"...It runs rough. It got a tune up (spark plugs, distributor cap and rotor) and it helped a lot but it still runs rough. I don't know why but it doesn't make any knocking or otherwise funny noises.

Just want to see what I should be looking at to make this truck legal to drive, and how much it'll cost. Heck, is it even worth purchasing?

Thanks,

Steve

[00Silverado4x4]

Welcome aboard. I'm sorry I don't have any helpful ideas off hand, if you do a search for those codes you should come up with some ideas. However personally I'd take it to a good shop/dealer and have them take a look at it and give you an estimate of what is wrong rather than guessing and wasting your time and money.

[1997SierraSLT]

1996 is the first year of the horrific Vortec 5000 & 5700 engine and it's a complete POS that lasted until 1999-2000. Constant fuel injection system problems from a piss poor CSFI poppet valve design and internal/external coolant leaks from a piss poor intake manifold design.

[2018GMC]

My 97 has 200k on the original engine and transmission. Runs GREAT. Yes it has had 1 intake manifold gasket in its life and 2 fuel pumps. I still have the mechanical SFI fuel injection. Works fine for me.

 

Some people upgrade to Multiport fuel injection.

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=csfi+to+mpfi

 

If I drive 60 - 65 I can get 20 - 22mpg. City is more like 13 - 14. I would suggest you replace all 4 Oxygen (O2) sensors. The 2 sensors BEFORE the cats matter the most, as they tell the computer to adjust the fuel mixture. The 2 sensors AFTER the cats only function for emissions (tell you if your cats are working or need replaced).

 

After replacing all 4 of my O2 sensors, I gained 2 - 3 mpg. Bosch O2 sensors are inexpensive on www.rockauto.com compared to the local parts stores.

 

-Individual Codes Present:

 

P0134, - 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

 

P0300 - Random Misfire

[ifixedit]

I am so glad MN got rid of the stupid emissions tests, while it was going it was a complete joke. Really, how many people are running around in 1977 Granada's?

 

I've got a 98 Yukon with the 5.7 and 203,000 rounds and yes it had the intake gasket issue which I replaced last winter. Other than that the thing runs flawlessly and I literally have not touched it other than routine maintenance since I bought it in 2000. I also purchased a 99 Tahoe my son drives that has just over 100,000 miles on it, sweetest running 350 I've encountered in quite some time.

 

Get the thing scanned for codes, you might have a bad MAP sensor and it's just running too rich. The MAP sensor on my 98 went bad and the light on the dash came on, the thing also lost what felt like about 50 HP and got sluggish when it happened. I put in a new MAP sensor and the difference was night and day. Could also be o2 sensors. Other than that I wouldn't be too afraid of these trucks, mine have taken a beating, run great, and keep coming back for more, there's a ton of them running around here yet!