Hi guys,

I guess I made the mistake of my life when I sold my XJ and got myself a 1999 4.7 WJ....

So here's what’s happening...
Recently I was getting the P0432 Code (Main Catalyst Efficiency below Threshold Bank 2) and I was ignoring it for a while, until my car suddenly loss power while driving on the highway... I was going around 60Mph and tried to pass another car, when it started to make some weird noises and loss power completely (Luckily it was midnight and not so busy)... I pulled over and tried to figure out what it is, there was a weird burning like smell and when I started the car one more time, it cranked, moved couple of feet and loss power again, the car is not stalling, but the RPM is climbing up to 3000RPM and then falling to 500-700RPM and even if I floor the pedal, it is not climbing back again....
If I shut the car down for like 5 minutes, it works again normal but it stops back, after around 5-10 minutes...

My check engine light was on for P0432 but after this, I started to get the following codes P0432 - P0174 - P0206 - P0407 – P0417... and maybe couple more...

My mechanic thought that it was the fuel pump, then he checked the fuel pressure which was around 58Psi and he eliminated that factor (Maybe it was running normal when he checked that I don’t know) , and he said that it sounded like exhaust back-firing and suggested to change the catalytic converters... There were 3 of them, 2 on Y pipe and one before the muffler... So we got 2 universal cats, welded them on the Y pipe and eliminated the one before the muffler (they all looked clogged by the way) the check engine light went off, everything was normal for an hour of driving and then started to do the same thing again...

I'm desperate now, I'm afraid to get the fuel-pump and get stuck with it again...

Please.....Anybody faced the same problem? Any solutions or advices?
and thanks for the reading the thread...

Best Regards
Leon

 

Did you check any of the O2 sensors while the cats were off? Maybe TPS?

 

I was suspicious about the O2 sensors all the time, but do they really effect the engine's work ability to the point of getting stuck?? I thought that all they do is control the emissions and tell the computer that your catalytic converters are working fine or needs to be replaced..... And what's the exact function of the TPS? And how much does it cost?

 

And is there an easy way to check the efficiency of the O2 sensors?

 

Did you find out what the burning smell was initially? Was it the O2 wires?

 

I don't know, the same smell is coming back after the engine is losing power, if the wires are bad, they should smell all the time... it's smelling like burn or exhaust burn ... i'm going to check everything tomorrow one more time... i'll appreciate any advice, to pay extra attention on the suggested points...

 

Check the O2 wire where they go down to the sensor.. sometimes the wires get fried by the exhaust pipe and are hard to see. but will give you false reading to the computer. sometimes making it do wierd things.. Just a thought since you said it starts that when it gets hot..

 

If it's the wires you smell, then no I would think you would only smell them when it warms up and starts burning again. Regardless I would replace the O2 sensors anyway as a bad sensor could cause your vehicle to run rich and kill the catalytic converter, so that might have been your problem in the first place. How many miles do you have on it? What kind of mpg?

 

I have around 135,000 miles on the clock and according to the truck's computer, i'm getting around 13.7 mpg....

 

Anybody thinks that it might be the TPS? Or kick down cable??

 

While I am not exactly sure of why your jeep is possessed, but I would lean towards the TPS because that affects the engines performance (RPMs) in relation to your foot on the go pedal. The kickdown cable affects the movement of your jeep. I would think that the kick down cable has no effect on erratic RPM signals and engine cutting out.

 

Thank you guys for your kind efforts, I just replaced one of the O2 sensors (bank 1 sensor 2) downstream and it's running like a champ for now (knock on wood) ....

 

crazy but my 98 jetta gl has this exact same engine code issue, i have not done anything to it and still continue to drive it normally.. wondering if i should pay a little more attention to it now. also i have a hole in my back muffler so i think that could be whats resulting in the code i am not wanting to pay so much for a new catalytic converter if i don't need one

 

If you need exhaust parts, check this site www.performance-curve.com I got 2 cat converters, plus a muffler for 156$ shipped to my door and it arrived within 48 hours, I placed an order through the phone, the sales guys are really very knowledgeable and they helped me a lot.... hope it helps