1988 Ford F-150 inspection failure

STARMAN75002

MEMBER
1988 FORD F-150
V8
2WD
AUTOMATIC
100,000 MILES

I have a 1988 F-150 I failed inspection 3 times. I relpaced pvc valve, plugs, idle air control valve TFI module and two cats yet it still fails on high NOx on high rpm drove it about 100 miles on new cats installation what am I misssing. Truck runs like a new truck but failing inspection. The only thing I have'nt changed is the o2 sensor, my engine light comes on after engine heats up. Also truck jerks when I press on gas and while i'm driving but all the time. I changed fuel filter also.

3 Replies

CJ MEDEVAC

MECHANIC
11,004 POSTS

See my profile

I do not know your rig much at all, for I am a CJ man.

I really was waiting for one of these computer car wizards to answer you.

Since they haven't yet, I know how important it is to get your rig fixed quickly.

You came here for HELP, as I did many months ago, this is sorta my hobby, while injured.

Here's something you may try to escalate things!

Did you have your codes checked?

Have it done FREE at Autozone or Advance Auto.

This may tell you its a Sensor problem, that may be screwing you up now.

They can code you or maybe retrieve stored codes, they know alot there, for they deal with this sorta stuff alot.

Sometimes they will show you exactly the problem, then sell you the part to fix it!

A Bad O2 sensor tells your computer NOTHING about your particular vehicles AIR/FUEL RATIO...in order for you to run PEAK BURNING!

When you 1st crank up, a GOOD O2 sensor, does not feed the computer info either! It has to Warm up, and have exaust flow over it, before it works.

The ONLY reason the vehicle runs the first several minutes is because......the GEEK SQUAD gave it a program of VALUES, that will keep it running (sorta no matter what..... but not as effecient, if it were getting "Real World, Now Info from the sensors)

With a Bad sensor, the computer relies on Those values all of the time.(you usually run really rich)

See your manual or your parts guy, you may have MULTIPLE O2 SENSORS.

Love, Turddog

Please reply either way, whether I helped or not.

I am a member as you are, no pay for me here!

Love, Turddog

THOUGHT A LITTLE "GRIN", MIGHT CHEER YOU UP !

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Sunday, April 4th, 2010 AT 3:36 PM

STARMAN75002

MEMBER
2 POSTS

Thanks for the quick response. I've already tried autozone my truck is too old check codes with their computer. I'm really frustrated at point with all the money spent and still having emissions problems. I do all my own work on my vehicles and never have had been so frustrated with no results. May have to break down and take to dealership for code errors, o2 sensor is only thing left. Love my truck still great condition and plan to customize with crate motor and new transmission. Just trying to keep running for another year before I start my project. Still paying on wife's car or I would start now.

Thanks for the help.

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Sunday, April 4th, 2010 AT 3:57 PM

CJ MEDEVAC