I pulled the codes while running a KOER test and got the code 72. Haynes says insufficient change in MAP/MAF sensor during dynamic test. I did a search and really did not find anything on a code 72 so I could use a little guidance as to what I should do.

Will this code have any affect on mileage or performance? I'm guessing that any engine code almost has some tiny amount of affect with performance and mileage.

Question, does my 1995 MAF 302 have both a MAF and a MAP sensor, I thought it did but cannot find the MAP sensor.

So where should I start? I just cleaned my MAF sensor 2 weeks ago, with carburetor cleaner, thats not the problem is it?

There is a slight chance it is code 172, I couldn't tell whether there was one blink telling me to get ready or not. I went blink, pause, 7 fast blinks, pause, 2 fast blinks, pause, 1 blink, pause 7 fast blinks, pause, 2 fast blinks. But I just replaced my o2 sensor about 400 miles ago.

 

Anybody got any ideas? Is my MAF sensor going bad? Maybe I didn't rev it high enough long enough while doing the dynamic test? Anybody got any advice as to where I should start checking things?

 

To start with a 95 only has three number codes so it is not a 72.
A 95 302 does not have a MAP sensor.

172 = right or rear HO2S = system indicates lean
You only have one HO2S sensor.

Possible Causes:
Fuel injectors, HO2S, Secondary Air Injection (AIR) system, PCV/Hose, Vacuum,or CANP.

There is not a 721 code.

 

A 95 would be a 3 digit code, not 2.

Going on what you posted you'd have a 172 not a 72.

KOER 172 HEGO sensor circuit indicates system lean (right side)

Test the fuel pressure at the rail, also check/repalce the fuel filter.

Slight chance you may have got a bad O2 sensor, you can test it via the manual you have.

You do not have a MAP sensor they are one or the other. MAP = speed density or MAF = mass air flow. You have the better one, well better for performance upgrades that is.

 

That's code 172. It's not telling you there is a bad O2 sensor, it's telling you the motor is running lean(on the right side if you have dual O2 sensors). Possible causes are a broken/cracked exhaust manifold, dirty fuel injectors, or a gasket leak on the intake.

 

Thanks you guys. Those suggestions will give me some good places to start. I just replaced the fuel filter about 200 miles ago, and I can't remember if I reset the computer or not. I only have one O2 sensor. I'll check for cracks and leaks. I would check the fuel pressure but I don't have a gauge. I did check the vacuum line going to the FPR and it smelled faintly of fuel, so if you pressure regulator goes bad will that cause less fuel pressure?

 

A failing FPR may or may not affect fuel pressure, a gauge is the only way to know. There should not be any fuel on the vacuum side of the regulator though, you should pull this line off with the engine running, if it leaks replace the FPR anyway.

 

I guess I should try running on the back tank, since I usually just use the front one, because the pump in my front tank may be going bad and not giving enough fuel pressure. So if I reset the computer and then run strictly on the back tank, and the code doesn't show up then I would know that it has something to do with the front tank right?? Because I don't have a fuel pressure gauge and I don't want to have to pay someone for them to check it, so I could at least check this first, even though there is only a small possibility that it is this.

 

A gauge is about $30 at sears or any parts store. You only need to buy it once, and it will help you for the rest of your life. I've used mine a half dozen times in the course of troubleshooting issues.