Dodge Nitro Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
I all, Thanks for your assistance in advance.

I bought this car as a graduation present for my son.

When I picked it up it was fine. I drove it from AZ to CA and on the way about 10 miles, the CEL came on. Well 100K miles and from what I could see had been neglected which was evident in the purchase price.
Saw no decrease in power or overheating and there was a very slight misfire at idle. Since I was going to do a lot of general maintenance to it didn't bother me. got a good 24mpg in the 300 or so miles. Without turning this into a graduation essay here is what I have done so far.

Symptoms

P0300 code
The system rich condition (vacuum leak maybe)
Hard start and some times no start.
Miss fire on the #3 cylinder (wondered why I wasn't getting a p0303)
Sometimes would start with no problem but put your foot on the gas and nothing, it would only idle and misfire. If I stepped on the throttle a little till it would move a little faster it got warmer, 1-2 minutes then everything would seem ok (Still CEL P0300). Driving down the highway everything is good.

What I found:

Mismatch in fuel injectors (different brands)
A leak in the intake manifold gasket(full of silicone).

The hard start or no start and rich condition seem to be resolved. I believe that may have been the fuel pump and intake manifold gasket.

Here is what I have replaced

Brand new fuel injectors (Bosch)
New intake manifold gasket
Brand new plugs (Bosch)
Brand new crank sensor
Brand new cam sensor
4 new O2 sensors
New serpentine belt
Dropped and flushed the gas tank and replaced the fuel pump
New oil and filter and air filter.
No water in the oil.

I replaced most sensors as this is an 11-year-old truck. It didn't cost that much but that cam sensor is a PIA.

One last thing, When driving with the CEL on I had to swerve to avoid hitting a cyclist and guess what, the CEL disappeared! A few minutes later, a ping with CEL flashing then solid.P0300 again.

I am out of ideas. Wiring issue needle in the haystack maybe? The only other sensor that I have not changed is the temp. The throttle body is black as night but they would still run just not as efficiently.

I am open to any ideas and correction here.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #3
Extra info

Short term fuel trim bank 1 at -4.68
Long term fuel trim bank 1 at -12.83
Short term fuel trim bank 1 at -3.96
Long term fuel trim bank 1 at -32.6

Vacuum leak?
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,305 Posts
P0300 Random/multiple cylinder(s) - misfire detected. Possible causes; Spark plug(s), HT lead(s), injector(s), ignition coil(s), low compression, wiring.
R/T so I assume a 4.0?
Check the pipe to the EGR valve. We had another member with the 4.0 who found it loose, corroded, moving.

Was the timing belt changed at 100K miles?
Only platinum plugs for the 4.0. ZFR5LP-13G
There is also an Ignition capacitor 1 bolt ground and 1 post terminal.
I believe it is under the lower intake manifold on the right side.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #5
Thanks Nitro Nut!

I sat and watched the really long and comprehensive youtube video on the same kind of symptoms am getting which ended up with a bad head. I will start with the EGR tube. I did find it loose at the EGR and tightened them up when I changed the plugs. I should have checked to see if the gasket was still there and or damaged tube. I have installed a new gasket at the intake plenum EGR connector. I will start there but after that, it's going to be a leak down test next unless there is a way to do a compression test with the plenum off.
 

·
Registered
Joined
·
5,073 Posts
maybe a good idea to remove the rocker covers and check the camshaft and mountings these can get worn and cause a intermittent issue on the 4.0l.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
Hi all.

Thanks for all your advise, without this, I wouldn't have succeeded in this repair. This is why I join forums to the real deal advise that is prevalent here. No um ah maybe its all just straight experience. Shout out to nitrogen for the next step in the process of a leak down as I would not have thought of checking for play in the cams etc.

The issue was the EGR tube fasteners and no gasket. The previous "vendor" had obviously had some issue, tried to fix something, lost the bolts, replaced them with some others that were available and just reset the CEL. The EGR tube bolts were incorrectly replaced with 10 mm bolts that were 5 mm too short and were interfering with the tube due to the large press fitted washers that were too large to tighten down as there was no clearance even to get a socket on them. There wasn't even a $2 gasket there. Fortunately, they had Philips heads so I could use a 1/4 inch socket with a large Philips insert from my screwdriver set to get them removed. I got new 8 mm cap screws 10 mm washers and a new gasket and all is well. It has been about 70 miles and a lot of fuel trim monitoring to find that this was the problem. No pending codes. I will keep you all posted.

6 pack later, thanks a million.

:)
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,305 Posts
Whoot! Thanks so much for getting back to us. You'd be amazed how many folks don't. Happy motoring!! :cool:
 

·
Registered
Joined
·
19 Posts
Question everyone, I have a 2008 SLT 3.7 that keeps having intermittent issues with the Engine Light going off if I let it idle too long. The DTC is reading "misfire detected". Could I also have an issue with a loose EGR? I've replaced all the plugs and all the coils. I was going to give the knock sensor a try, until I came across this thread about the EGR. Any advice is greatly appreciated.
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,305 Posts
Question everyone, I have a 2008 SLT 3.7 that keeps having intermittent issues with the Engine Light going off if I let it idle too long. The DTC is reading "misfire detected". Could I also have an issue with a loose EGR? I've replaced all the plugs and all the coils. I was going to give the knock sensor a try, until I came across this thread about the EGR. Any advice is greatly appreciated.
Welcome back steviep187. Its been a Long time.
The 3.7 and 4.0 are different beasts as to EGR location. But it won't hurt to look at it.
 
  • Like
Reactions: Nitrogen

·
Registered
Joined
·
19 Posts
Thanks! It has been a while. Thanks for the reply, I will give it a look. I'm pretty much running out of ideas at this point. :)
 

·
Registered
Joined
·
5,073 Posts
did you use the correct type spark plugs, the 3.7 will only run correctly on copper plugs ?.
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,305 Posts
Knock sensor.
 
  • Like
Reactions: Nitrogen

·
Registered
Joined
·
4 Posts
I all, Thanks for your assistance in advance.

I bought this car as a graduation present for my son.

When I picked it up it was fine. I drove it from AZ to CA and on the way about 10 miles, the CEL came on. Well 100K miles and from what I could see had been neglected which was evident in the purchase price.
Saw no decrease in power or overheating and there was a very slight misfire at idle. Since I was going to do a lot of general maintenance to it didn't bother me. got a good 24mpg in the 300 or so miles. Without turning this into a graduation essay here is what I have done so far.

Symptoms

P0300 code
The system rich condition (vacuum leak maybe)
Hard start and some times no start.
Miss fire on the #3 cylinder (wondered why I wasn't getting a p0303)
Sometimes would start with no problem but put your foot on the gas and nothing, it would only idle and misfire. If I stepped on the throttle a little till it would move a little faster it got warmer, 1-2 minutes then everything would seem ok (Still CEL P0300). Driving down the highway everything is good.

What I found:

Mismatch in fuel injectors (different brands)
A leak in the intake manifold gasket(full of silicone).

The hard start or no start and rich condition seem to be resolved. I believe that may have been the fuel pump and intake manifold gasket.

Here is what I have replaced

Brand new fuel injectors (Bosch)
New intake manifold gasket
Brand new plugs (Bosch)
Brand new crank sensor
Brand new cam sensor
4 new O2 sensors
New serpentine belt
Dropped and flushed the gas tank and replaced the fuel pump
New oil and filter and air filter.
No water in the oil.

I replaced most sensors as this is an 11-year-old truck. It didn't cost that much but that cam sensor is a PIA.

One last thing, When driving with the CEL on I had to swerve to avoid hitting a cyclist and guess what, the CEL disappeared! A few minutes later, a ping with CEL flashing then solid.P0300 again.

I am out of ideas. Wiring issue needle in the haystack maybe? The only other sensor that I have not changed is the temp. The throttle body is black as night but they would still run just not as efficiently.

I am open to any ideas and correction here.
Where is the cam censor located big guy? pic if available
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,305 Posts
Where is the cam censor located big guy? pic if available
The 4.0 camshaft position sensor is at the Left, front, top of the timing gear cover, below the generator.
 
  • Like
Reactions: Nitrogen
1 - 17 of 17 Posts
Top