I have a 02 Ranger Edge with the 3.0 engine. I went to start it this week, and I noticed it was revving higher than normal and idling very badly. I killed it and plugged in my code reader. It was reading error code P1121. After looking this code up, I decided to try cleaning the MAF sensor with MAF cleaner. After doing this and clearing the code, I cranked it again only to find the same code plus P1132 and P1152. These seem to be related to the O2 be sensors. What would be the next course of action in troubleshooting these codes?

Another useful piece of information is that I've discovered if I give it gas and rev it up to around 2,000 rpms, it begins to run smoothly and then you can let off the gas and it'll idle with no issue.

Thanks.

 

Welcome to the forum

You should post the code definitions with the codes since you probably already looked them up, lol

No one has them all memorized

And just an FYI,
P0xxx is a generic OBD code and its definition applies to all vehicle makers, Audi to Zotye Auto
P1xxx is a manufacturer specific code, so in this case its a FORD computer so a Ford only definition


P1121 Throttle Position Sensor(TPS) Inconsistent with Mass Air Flow Sensor
P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2

1121 means that if the throttle position sensor shows the throttle is 1/2 open then with a 3 LITER engine the air flow should be within XX to XY level, MAF sensor reads the WEIGHT of the incoming air so it is the only comparison the computer has to test both TPS and MAF
Cleaning the MAF sensor was a good idea and it should be done once a year, or at least every 2 years

But now you have the TPS to test, you need a volt meter and a sewing needle
The center wire on the TPS is the signal wire that goes back to the computer
With throttle closed it will show, .69 to .99 volts, under 1 volt
With throttle wide open(WOT) it should show 4.5 to 4.9volts

TPS is a "learned" sensor, on startup computer will establish TPS Closed voltage, and over time it will find WOT voltage when driver "floors it", lol

So it has a ratio from closed to wide open to establish 1/4, 1/3, 1/2 open throttle positions
Computer "knows" it is operating a 3 LITER engine, so engine can suck in 3 LITERS of air every 2 RPMs at WOT, so from there it is just math to know how much air should be coming in at any RPM and any throttle position.
And the MAF sensor should also show similar air flow, or code gets set

I don't think its MAF or TPS issue...........because you said it idled higher I think you have a vacuum leak
A vacuum leak means not all the air is flowing thru the MAF sensor, so it will be off, so won't be correct for TPS voltage match

And the Rich code is an air:fuel mix code, it means computer calculations are off, and calculations are based somewhat on MAF sensor data and with a vacuum leak it is off

So both codes could be from vacuum leak


Check vacuum hoses, PCV hoses are first


After engine is warmed up you can confirm a vacuum leak by letting engine idle and unplug IAC Valve, with IAC Valve unplugged RPMs should drop to 500 or engine should stall, either is good it means no vacuum leak
If idle doesn't drop then there is a leak

 

Actually listing the code descriptions didn't cross my mind. Sorry about that.

Thanks for the information. I've done a little troubleshooting, but I haven't pinpointed the issue yet. I got the engine warmed, and as soon as I unplugged the IAC valve, the RPMs dropped to nothing.

I also back probed the TPS and had someone slowly work the gas pedal. At rest, I was reading 0.95V, and as the pedal was slowly depressed, The reading rose to 4.55V without any noticable gaps.