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vincentjones1 01-31-2020 12:05 AM

Engine Question(s)
 
Hello everyone. I am new to this group. I have a couple of question(s) concerning my engine. The engine has 203500 miles on it. Recently I have been experiencing the following:
- Bad gas mileage
- Intermittent loss of power while driving
- While driving, the car feels jerky and rough
- Some smoke (O2 sensors are new; getting a lean code from the ODB2)
- RPM gauge has been acting erratically
- On the plus side, still idles great

My regular mechanic has been working on the Jeep for about 7 years and he cant locate the problem.
I took the Jeep to the dealer and they ran a diagnostic test (185$). They got the same lean code as my mechanic. That was it. The rest of the diagnostic test didnt show anything (the exception being low compression on #1). Didnt address the driving issue, even after they test drove it. Complete waste of money.

My question is this: Has anyone reading this experienced these things with their Jeep, specifically this engine? Any and all answers or guidance would be appreciated.

Thanks.

Vince

mukluk 01-31-2020 12:17 AM

Might help to fill folks in on what year and model Jeep we're talking about, what engine, what were the compression readings, and what specific fault code you're getting.

V8GCZJ 01-31-2020 04:49 AM

Quote:

Might help to fill folks in on what year and model Jeep we're talking about, what engine, what were the compression readings, and what specific fault code you're getting.
This still amazes me that people ask questions and NO vehicle/engine info? Just don't get it! We don't all have these...
https://vignette.wikia.nocookie.net/...20180906164510

vincentjones1 01-31-2020 09:53 PM

2007 JK Wrangler (4 door)



Engine: 3.8


Cylinders:
#1: 60PSI
#2: 65PSI
#3: 70PSI
#4: 60PSI
#5: 70PSI
#6: 65PSI


Lean Code(s): P0171 and P0174


That should cover it. And I hope that helps.

Arty McGeep 01-31-2020 10:03 PM

If your compression readings were that low, your engine wouldn’t even run at all. Sorry. Try again.

mukluk 01-31-2020 11:42 PM

P0171 and P0174 show both upstream O2 sensors are reading lean. Factoring in the poor fuel economy as well, I'd say chances are quite good you either have a bad exhaust leak near your upstream sensors that's causing a false lean condition, or you have an aftermarket "performance" chip installed that's messing up the upstream sensor signals.

The compression figures you posted are quite suspect. As noted, if they were truly that low it's unlikely your engine would run or at the very least it would be burning so much oil you'd think it was a two stroke.

Pull your sparkplugs and have a look at the portion that goes in the combustion chamber. Do they look black and oily, black and sooty, tan or light grey, or are they white?

vincentjones1 02-06-2020 09:48 PM

After speaking with a few mechanics, they were in agreement with what you said. If the compression readings were that low, the jeep would have a very rough time of operating. The dealer did the compression test. If it was that bad, why wouldnt they have said anything? I will have to deal with them later.


Anyways, what can anyone tell me about the electronic throttle control system? If it is good or bad, other than the warning lkighht coming on.

jtec 02-07-2020 05:36 AM

electronic throttle, the symbol is illuminated, SO you will need to scan for codes.

X3 on those compression #s something is wrong with them...do over suggested.

the p0171 p0174 as mentioned LEAN some suggestions above - a scanner looking at live data would be a faster glimpse and time wise quicker than typing this reply ;)

vincentjones1 02-10-2020 10:47 AM

Quote:

Originally Posted by jtec (Post 40868275)
electronic throttle, the symbol is illuminated, SO you will need to scan for codes.

X3 on those compression #s something is wrong with them...do over suggested.

the p0171 p0174 as mentioned LEAN some suggestions above - a scanner looking at live data would be a faster glimpse and time wise
quicker than typing this reply <img src="https://www.jeepforum.com/ubb/wink.gif" border="0" alt="" title="Wink" class="inlineimg" />

I replaced the electronic throttle control module but it is still running like crap. Plus the flashing check engine light came on this morning.

jtec 02-11-2020 07:09 AM

what codes are showing?

Why did you replace 'module' ?


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