- Joined
- Aug 7, 2007
- Messages
- 1,733
- Reaction score
- 536
- Points
- 113
- Location
- Costa Mesa, CA
- Vehicle Year
- 2002
- Make / Model
- Ford
- Engine Type
- 4.0 V6
- Engine Size
- 4.0 SOHC
- Transmission
- Manual
- 2WD / 4WD
- 4WD
- Tire Size
- 33"
A couple days ago I was driving about 80 mph, keeping up with SoCal freeway traffic. Suddenly, I noticed I was slowing down without letting up on the accelerator pedal. I stepped on the pedal a little and it just bogged. I moved to the right lanes as it slowly reduced speed. I had to feather the pedal to try to maintain a reasonable speed. After about 3/4 mile I reached an exit and was barely able to keep it at 60 mph and still losing speed. I had to stop at the light and it idled fine. When it was time to go, I had very little power and it took a long time to get up to 40 mph. I tried to time the lights so I would not have to accelerate again. By the time I got home, (about 2 miles) it was getting worse.
I bought a new fuel filter because it was due anyway and hoped it would solve the problem. I installed the filter a day later and started the engine. It ran fine and I took it for a drive. It ran normally to my first stop (2-3 miles). I then headed back home and it was still running normally. I decided to go on the freeway to give it a good test. I was thinking, could I be that lucky?
At the onramp I floored it in 2nd gear to give it a good test. Initially it accelerated very well but when it got to about 4,000 rpm it started bogging again. I let up a little and it continued to accelerate. I was able to get up to freeway speed but could not floor it. I then exited and drove on side streets for a while. The longer I drove the worse the power got. I was barely able to get home again.
The next morning I took it for a test drive again and it had low power right away. I checked the fuel pressure and it would pump to 65 psi and drop to slightly over 60 with the engine off. With the engine on it would maintain somewhere above 60 psi. I pulled the MAF and filter for cleaning. The MAF didn't look bad but the filter was very dirty. Unfortunately, cleaning both made no difference in engine performance.
I was getting no codes the first couple times I checked but after playing with things a couple days, the "check engine' light came on and I got a P1401 code. This relates to the DPF EGR /sensor. I replaced that a couple years ago and think that code it just a symptom of the real problem.
I checked the vacuum and I get 17 at idle. When I increase rpm a little it drops quickly then comes back up to 17. If I rev it to around 2,000 rpm, the engine gets rough and the vacuum drops way down. The exhaust at idle is much more quite than normal and is not pulsed like it usually is. It has a steady stream of exhaust gasses and seems to be hotter than normal. At idle I can usually hold my hand at the exit of the tail pipe without feeling discomfort. Now, I have to pull my hand away after very short time.
I am leaning toward clogged catalytic converter(s). All 4 of them are original with over 251K miles. I can't imagine all of them are bad. I plan to remove the two rear ones to check out and try driving without them to see if that makes any difference. Will the engine run okay with the rear O2 sensor disconnected or just hanging?
I bought a new fuel filter because it was due anyway and hoped it would solve the problem. I installed the filter a day later and started the engine. It ran fine and I took it for a drive. It ran normally to my first stop (2-3 miles). I then headed back home and it was still running normally. I decided to go on the freeway to give it a good test. I was thinking, could I be that lucky?
At the onramp I floored it in 2nd gear to give it a good test. Initially it accelerated very well but when it got to about 4,000 rpm it started bogging again. I let up a little and it continued to accelerate. I was able to get up to freeway speed but could not floor it. I then exited and drove on side streets for a while. The longer I drove the worse the power got. I was barely able to get home again.
The next morning I took it for a test drive again and it had low power right away. I checked the fuel pressure and it would pump to 65 psi and drop to slightly over 60 with the engine off. With the engine on it would maintain somewhere above 60 psi. I pulled the MAF and filter for cleaning. The MAF didn't look bad but the filter was very dirty. Unfortunately, cleaning both made no difference in engine performance.
I was getting no codes the first couple times I checked but after playing with things a couple days, the "check engine' light came on and I got a P1401 code. This relates to the DPF EGR /sensor. I replaced that a couple years ago and think that code it just a symptom of the real problem.
I checked the vacuum and I get 17 at idle. When I increase rpm a little it drops quickly then comes back up to 17. If I rev it to around 2,000 rpm, the engine gets rough and the vacuum drops way down. The exhaust at idle is much more quite than normal and is not pulsed like it usually is. It has a steady stream of exhaust gasses and seems to be hotter than normal. At idle I can usually hold my hand at the exit of the tail pipe without feeling discomfort. Now, I have to pull my hand away after very short time.
I am leaning toward clogged catalytic converter(s). All 4 of them are original with over 251K miles. I can't imagine all of them are bad. I plan to remove the two rear ones to check out and try driving without them to see if that makes any difference. Will the engine run okay with the rear O2 sensor disconnected or just hanging?
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