I have noticed an occasional smell of gas, that seems to come from the exhaust on startup on cold days. Only after sitting over night about 15 hours. Not all the time.

Could this be a sticking injector or is one going.
I do have a dying rear 02 as well, runs at about 50%

Last thing could injector cleaner help or is it just time to replace them

 

Injector cleaner might help but if you D2 is high mileage, then it is probably time to pull the injectors and rehab them. There are tons of kits on ebay that replace pintle caps, o-rings and filter baskets.
This video is really good to show how to clean a fuel injector:

 

D2's will run rich on a cold start up. I've seen several bad ones in my day & usually they stick open and dump fuel into the cylinder. Which causes a hard start, due to gas in cylinder being pushed past the piston rings. Usually the oil will start to smell like gas. If it starts rough or hard to start or oil smells like gas investigate before you damage your bearings!!!!

 

@Best4x4 no hard start she still starts on 1 or 2 rev and starts clean. Just noticed it when I was scraping ice when it was around 5 or 6 deg F. And only 1st thing in the AM, when it happens. Today it was fine. I am tad OCD about truck stuff though

 

Like Best says, they will run a little rich on a cold start, this isn’t just LR’s. It’s a bit like choking a carbureted engine but no where near as over rich as that.

 

Thanks guys I will monitor for a few days

 

Watch the 02 sensor voltage and fuel trims. If you have a leaking injector it will have high fuel trims at a minimum and if it is so bad the fuel trims are maxed the 02 voltage will be near 1 volt.

 

My good friend had a 96 D1 which started acting weird by having multiple misfires on bank 1. We suspected a blown HG between 2 cylinders and we were right. He replaced the HG, and put the engine back together. It fired up and then quickly died (I wasn't there) and after several attempts he noticed his fuel gauge was reading E with the light on. He figured it evaporated due to the heat in his garage (he had been working on the fuel system at the same time as the HG and installed a new Fuel Pump). He ran and got 5 gallons of fuel, and tried to start it. It acted like the starter was dying or the battery was weak so he jumped it off, and it came to life barely. He called it quits, and eventually I was able to stop by and look at it maybe 2 weeks later. He had attempted multiple start ups before I could make it out there and it would start then just die on it's own at idle and refuse to restart after that. I got there and started looking things over. His fuel was low again and I found that extremely odd. When I pulled the dipstick I was like well I think I've found your problem. It was up about 6 to 8 inches past the full MARK and smelled of nothing but fuel. I then removed the intake tube and to my horror fuel/oil mix was sitting in the intake! I told him he had a fuel injector or injectors dumping fuel straight into his engine and it was basically hydro locking on the fuel and it was going past the piston rings and straight into the engine. We pulled the plugs and thank goodness it was just 1 cylinder #6 which was full of fuel. He had it parked on a slope and wanted to drain the crankcase of the fuel/oil and I said ummm get some nasty clothes and a BIG container.

He climbed under his D1 and when he removed that drain plug it was like a scene out of the oil movie "There Will Be Blood" He was covered in fuel/oil and it was gushing down the driveway (he had just moved in 2 months before). He got the plug back in and was like OMG..... We ran and got some sand across the street to soak up the fuel/oil as best as we could. I then had to leave, but I told him to finish draining it, and replace the injector or injectors (he had a spare fuel rail with injectors). He swapped it all out, changed the oil and it was fine for a month or two, but on a trip out to see me he lost all oil pressure and she locked up shortly after that mess. We installed a spare engine he had and his D1 is cruising around no problem to this day. He still has the old block, and plans on a complete rebuild as it didn't explode or get hot when it coasted to a stop.

Just keep an eye on it, and if you want pull the plugs and see if one looks wet with fuel. You will certainly know if an injector is leaking if you strongly smell fuel, the plug is wet, and possibly fuel is still in the cylinder.

 

@Best4x4 so far :

• no more gas smells it is warmer
• oil level is good
• fuel trims are good
• 3 out of 4 o2's are good the 3rd is at about 1/2 voltage - passenger rear it is dying
• fuel consumption normal

 

Richard I’m pretty sure the rear O2 sensors do nothing to trim fuel, they only monitor how the Cat is functioning. If a rear sensor isn’t throwing a CEL, it won’t affect anything.