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I'm at my wits end


KingTut

Active Member
Joined
Nov 9, 2011
Messages
27
Vehicle Year
1999
Transmission
Automatic
Heys guys, Ive got a 1999 Ranger 4x4 that is running rich at idle. I've searched on here and read various things that could possibly cause a rich mixture. So I took it to the shop to have the codes pulled which included the following: P0135, P1132, P0155, P1152, P1400, and P0141. Majority of the codes were due to bad O2 sensors so I had them replaced. However, two of the codes were related to the EGR valve. The shop also tested the fuel pressure which they claim was in "normal operating range".

Since having the O2 sensors replaced and the EGR valve, the truck still runs horrible at idle. The things that I have replaced include: new plugs and wires, new coil pack, new IAC, new MAF sensor, new coolant temp sensor, new fuel injectors, new PCV valve, and a new airfilter. After replacing all of mentioned items I'm still getting a P1132 code and a P1152 code which is the O2 sensor registering a rich condition.
To give an idea of how the truck is running, when I first start it up in the morning it runs fairly decent until the idle drops to normal operation. After that the truck stumbles and rocks and sounds like a misfire. Black exhaust is coming out the tail pipe but its not thick. However, it has a strong fuel smell. When I'm driving down the road everything feels fine the problem only occurs when I stop at say a stop sign or when I just let it idle in neutral.

What else could I try to solve this problem? I'm almost to my wits end with this truck. Thanks guys
 
Is there any way to test the fuel pressure regulator? I've read somewhere that if you unplug the vacuum to the fuel pressure regulator and fuel is in the vacuum line, then it's more than likely bad. I've tried this and the line seemed dry.
 
Did you personally replace the oxygen sensors, or did you have Skippy-Lube do it?

I have seen situations similar to your caused by a bad oxygen sensor and then continued by someone putting a catalyst monitor in an O2 sensor hole.
 
I replaced the passengers side downstream O2 sensor and had the drivers side installed because it was stuck in the exhaust pipe. I personally took them the O2 sensor and watched as it was installed. The only thing that I haven't tried is the TPS. Would this cause the truck to run rich?
 
That shouldn't do it, no. Are you using factory parts? Some of that vatozone crap is just that- crap. I've had an IAC do this before, ADSM08 told me to clean it and it ran perfect after that. I always replace with motorcraft stuff... reduces the chances of replacing over and over.
 
Yeah unfortunately the IAC was from autozone. If the one that I got from autozone was bad wouldn't it throw a check engine light? The reason that I mentioned the TPS is that I'm having delayed shifting from 1st to 2nd and from 3rd to 4th. I forgot to mention this. I read somewhere on here that a bad TPS would cause a delayed shift. Thanks for the responses guys. I will get this figured out eventually.
 
I replaced the passengers side downstream O2 sensor and had the drivers side installed because it was stuck in the exhaust pipe. I personally took them the O2 sensor and watched as it was installed. The only thing that I haven't tried is the TPS. Would this cause the truck to run rich?

When discussing O2 sensors, upstream O2 is the one that monitors the air/fuel ratio, they are installed before the cat. Downstream O2 is the catalyst monitor and has no effect on engine operation, it is installed aft of the cat.

I'm pretty sure that your 99 has the fuel pressure regulator in the tank. The part on the fuel rail is a damper.

My only suggestion would be to disconnect the vacuum line to the egr valve, plug the line and take a drive like that. If the EGR regulating solenoid is stuck open, it'd run crappy at idle.
 
Yes you are correct. I changed the two upstream O2 sensors. I will try that out and report back with results. What am I looking for while driving the truck with EGR vacuum plugged and disconnected? Should it run better or get significantly worse? One last thing, I disconnected the the vacuum to the EGR and put my finger over the vacuum line to plug it but I didn't feel any vacuum. Is the vacuum created by the exhaust flow or....? Thanks
 
Ok, so I took the vacuum line from the EGR and plugged it. Drove it down the road and no change. Also while I was at it I changed out the TPS. No change after that either. Also unplugged the IAC while truck was running and it stalled. Unplugged the MAF and there was no change there either. With that being said here is the list of all the things that were replaced.
1. Plugs and wires
2. IAC valve
3. Coil pack
4. EGR valve
5. Fuel Injectors
6. PCV valve
7. TPS
8. MAF
9. Coolant Temp Sensor
10. air filter

What's left? A new ECU? I should have a fairly new motor if I get this fixed ;)
 
Yes, its the 3.0 Flex fuel engine.
 
whats the vacuum readings like?
 
I'm not sure. I need to have a vacuum test done. When I took it to my local shop, I asked them if maybe I had a vacuum leak. The guy told me that since it was running rich, a vacuum leak was ruled out becuase it would cause the truck to run lean from extra outside air entering. I'm not sure if maybe that's were you were heading with a vacuum leak, bobby, but I may take it somewhere else for a second opinion. Anythings a possibility at this point.
 
You have replaced the O2 sensors, but try just disconnecting them. You may still have bad O2 sensor(s) for whatever reason. Only takes a few minutes to check.

CraigK
 

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