69401
New Member
- Joined
- May 29, 2009
- Messages
- 3
- Reaction score
- 0
- City, State
- WY
- Year, Model & Trim Level
- '99 XLS
I have a slowly developing rough running 1999 Ford Explorer 4.0 OHV. I changed heads in 2007 due to a cracked left head. (approx. 110,000 miles) It developed a leak in the back catalytic converter around 2010 that I have never replaced as I didn't drive the vehicle a lot back then. I also changed the fuel pump in 2008 and 2014. In the last year or two, I have started driving it more and this summer, it has started running rough. At first, I would just notice a momentary hesitation maybe once a week or so. Also, some time around this time, I noticed my engine running warm one day and so I filled the coolant level when I got home. This was probably sometime in June.
Around the 1st of September, it started missing more consistently on acceleration and a check of my scanner read a "Pending" code of misfire cylinder #6. I checked the plugs and noticed that they were very old, with no visible electrode left. I thought this was the problem and so changed the plugs and wires. (Now about 170,000 miles) The missing went away for about a week but them started appearing randomly again. Typically when the vehicle was initially started and then also at idle after the engine was fully warmed up. After initial acceleration, the missing would disappear. I checked the vacuum on the engine. It took 20-30 second to build up to 21 psi. This seemed slow to me but I'm not sure. I also checked the fuel pressure and it was reading 60 psi with a slight drop if I hit the accelerator. I also pulled the vacuum line to the fuel pressure regulator. This produced no change in the vacuum pressure. I changed the fuel filter and thought maybe too much fuel was getting to the engine since the Haynes manual said the reading should top at around 45 psi and have a slight increase when the vacuum line is pulled.
Then on October 10, I noticed my engine running warm again on the way home from work. I quickly plugged my scanner in and was running between 210-235. I got home and again had to fill the whole radiator with coolant. The engine was also beginning to run rough at idle more consistently. It also threw a missfire code again on $6.
Yesterday, I again ran out of coolant and the engine ran warm for a mile or two until I got to a store to get some water. The engine was now running really rough at idle most of the time but again after initial acceleration, would run okay. With this obvious coolant leak, I thought maybe a blown head gasket leaking coolant into the combustion chamber. I had time to do only a compression check of Bank 2, #s 4, 5, and 6. When I pulled the plug on #6, I thought I might find evidence of a coolant leak but instead found the my new plug was covered in oil. It built 90 psi on the first stroke and after 4 strokes had 140 psi total. Cylinder 4 plug was nice and dry and the cylinder again built 90 psi on the first stroke and ended with with 130 psi total. Cylinder 5 built 120 psi after the first stroke and ended with 140 psi total.
I don't have equipment yet to do a leak down test or a chemical testing for combustion in the coolant. At first I thought head gasket or crack but with the compression check not looking too bad (from my limited knowledge) and after reading other posts here, I'm wondering if a manifold gasket might be to blame. I can't find any visible place for coolant leaks so that is throwing me off but maybe that is unrelated to the misfire issue.
Sorry for the long post. Any suggestions on where to look?
Around the 1st of September, it started missing more consistently on acceleration and a check of my scanner read a "Pending" code of misfire cylinder #6. I checked the plugs and noticed that they were very old, with no visible electrode left. I thought this was the problem and so changed the plugs and wires. (Now about 170,000 miles) The missing went away for about a week but them started appearing randomly again. Typically when the vehicle was initially started and then also at idle after the engine was fully warmed up. After initial acceleration, the missing would disappear. I checked the vacuum on the engine. It took 20-30 second to build up to 21 psi. This seemed slow to me but I'm not sure. I also checked the fuel pressure and it was reading 60 psi with a slight drop if I hit the accelerator. I also pulled the vacuum line to the fuel pressure regulator. This produced no change in the vacuum pressure. I changed the fuel filter and thought maybe too much fuel was getting to the engine since the Haynes manual said the reading should top at around 45 psi and have a slight increase when the vacuum line is pulled.
Then on October 10, I noticed my engine running warm again on the way home from work. I quickly plugged my scanner in and was running between 210-235. I got home and again had to fill the whole radiator with coolant. The engine was also beginning to run rough at idle more consistently. It also threw a missfire code again on $6.
Yesterday, I again ran out of coolant and the engine ran warm for a mile or two until I got to a store to get some water. The engine was now running really rough at idle most of the time but again after initial acceleration, would run okay. With this obvious coolant leak, I thought maybe a blown head gasket leaking coolant into the combustion chamber. I had time to do only a compression check of Bank 2, #s 4, 5, and 6. When I pulled the plug on #6, I thought I might find evidence of a coolant leak but instead found the my new plug was covered in oil. It built 90 psi on the first stroke and after 4 strokes had 140 psi total. Cylinder 4 plug was nice and dry and the cylinder again built 90 psi on the first stroke and ended with with 130 psi total. Cylinder 5 built 120 psi after the first stroke and ended with 140 psi total.
I don't have equipment yet to do a leak down test or a chemical testing for combustion in the coolant. At first I thought head gasket or crack but with the compression check not looking too bad (from my limited knowledge) and after reading other posts here, I'm wondering if a manifold gasket might be to blame. I can't find any visible place for coolant leaks so that is throwing me off but maybe that is unrelated to the misfire issue.
Sorry for the long post. Any suggestions on where to look?
