W00GYB00GY

I have a 1996 XJ 4.0 straight 6, and recently it has been running rough, I have to accelerate extremely slow or else my jeep won't go, and if I'm going 55mph or any speed and I try to press a little harder my jeep will kinda stall out, it wont shut off completely but it kinda freezes.

I straight piped my jeep a while back and have had no problems what so ever, and I know the code would come up for it (P0171) but it has never been an issue, and my check engine light never came on because I did the anti-fowler method.

But then I scanned my jeep today and this code came up...

P0172 (M) 1/1 Fuel System Rich A rich air/fuel mixture has been indicated by an abnormally lean correction factor.


Suddenly my jeep has thrown the P0172 for fuel system to rich...

Can anyone help out? I know I'll probably hear it for straight piping, but I have no smog tests and no inspections where I live.

rideordie66

did you put the o2 censors back on when you did the exhaust?

W00GYB00GY

Yeah, I only "removed" one of the o2 sensors to put the straight pipe on, then I welded a bung on the straight pipe and used the anti fowler method for the o2 sensor that I put back on.

So yeah I have both o2 sensors still on.

W00GYB00GY

So I replaced my TPS, and the first o2 sensor on the downpipe with a new one, and my problem still hasn't changed.

About a week ago I sprayed silicone on my belt to prevent the belt from squealing and I didn't no that was a horrible idea....FML, but I'm not sure if that has thrown the timing off or what but this problem started happening the same day I sprayed the silicone on my belt.

I will be driving and then when I let off the gas my car will almost stall out, If I tap the gas to go faster it wont work, but it isn't my transmission slipping, it feels like its something to do with the acceleration or linkage, or throttle I'm not really to sure.

When it happens, I can put my car in neutral shut it off and restart it, and I can drive it with no problems for like 10-15 seconds then it goes back to the hesitation/stalling problem.

Problem after problem.....any help is greatly appreciated!

Shadowwar

Check the fuel pressure.

W00GYB00GY

Here is a video I took of my jeep in action...

http://www.youtube.com/watch?v=aleHU...ature=youtu.be

When the problem happens in the video, my foot was on the gas pedal the entire time, I wasn't pressing it then letting go, then pressing it....let me know what you guys think...

W00GYB00GY

anyone?

Shadowwar

Definately seems like fuel starvation.. Did you check fuel pressure?

reddonkey

Checking the fuel pressure is a good idea. The fuel pressure regulator may be bad or the fuel pump its self. Rent a gauge from an auto parts store and check it. Then report back with the findings.

W00GYB00GY

Well all the sensors I checked were normal, I then checked the fuel pressure idling in my drive way and it was 45-55psi then I drove around with it hooked up, and when the problem started my fuel pressure drastically dropped to 20-5psi, then I would stall out.

So right away I knew it was the fuel pump, went to the parts store for a fuel pump and strainer and installed it and now we are good to go...I drove it for about 35 mins and the problem never happened. I will test it out later and drive around for longer just to be 100% positive but I'm pretty sure its fixed.

Thanks for all the help on here...you guys are awesome!