Intake Manifold?
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Intake Manifold?
I have a 2003 F-150 with the 5.4 engine with 190,000 miles on it. I bought it a year ago with 175,000 miles.
I have been having misfire problems with it for the last few months. It has thrown codes most cylinders, but the biggest problems have been on 3,7,8. I changed the coil packs.
When I have had a misfire that caused it to run rough, then I would get coolant on that plug.
A week ago, I did a pressure test on the coolant system. I pumped it up to 16 lbs, and it lost 1.5 lbs in two hours (is that good or bad?). However, the next day, I had bad misfires, and it ran terrible. I pulled the spark plugs- they were all dripping with coolant. I cleaned them and ran a compression test. I checked each cylinder three times- they all were between 140-150 psi.
The next day, I got another misfire on cylinder 4. I pulled the plug and cleaned it, and cleared the code, and have not had another misfire in about 400 miles (knock on wood). I checked for exhaust gasses in the coolant, and there weren't any-- I used the block tester (turkey baster looking thing) and the blue fluid. That should mean that I don't have a problem with the head gasket, cracked or warped head, right? However, I can see and smell coolant at the tail pipe.
I have heard that the intake manifold is a common problem. Is it possible that my troubles are stemmed from that? Is there a way to test it? Does anybody have experience with this problem?
Thanks,
Jeff
I have been having misfire problems with it for the last few months. It has thrown codes most cylinders, but the biggest problems have been on 3,7,8. I changed the coil packs.
When I have had a misfire that caused it to run rough, then I would get coolant on that plug.
A week ago, I did a pressure test on the coolant system. I pumped it up to 16 lbs, and it lost 1.5 lbs in two hours (is that good or bad?). However, the next day, I had bad misfires, and it ran terrible. I pulled the spark plugs- they were all dripping with coolant. I cleaned them and ran a compression test. I checked each cylinder three times- they all were between 140-150 psi.
The next day, I got another misfire on cylinder 4. I pulled the plug and cleaned it, and cleared the code, and have not had another misfire in about 400 miles (knock on wood). I checked for exhaust gasses in the coolant, and there weren't any-- I used the block tester (turkey baster looking thing) and the blue fluid. That should mean that I don't have a problem with the head gasket, cracked or warped head, right? However, I can see and smell coolant at the tail pipe.
I have heard that the intake manifold is a common problem. Is it possible that my troubles are stemmed from that? Is there a way to test it? Does anybody have experience with this problem?
Thanks,
Jeff
