I posted here before, but never really got a good answer. So I will try again and this time I have more symptoms and information.
Basically, when starting off the line from a dead stop the engine seems to be struggling until it gets to about 3500 rpm. The all of a sudden it feels like someone let off the brakes and all the power comes into play.
This is especially bad when pulling my car trailer with my show car on it. The longer I pull the load the worse the problem gets. It gets so bad that I can barely get moving without flooring it and waiting till the rpm's get up to 3500.
Also, after pulling a load for a long distance when I pull up to a light, the engine wants to die sometimes and I have to go into neutral and revv it up to keep it from dying. Once you revv it though it goes back to normal operation.
History: I bought the truck from a dealer with 93,000 miles on it for a daily driver beater type vehicle and immediately did a complete maintenance and professional check of the whole vehicle. Brakes good, flushed the brake lines, flushed the transmission and differential. I put a brand new three core radiator in it since I would be pulling my show car with it and didn't want any over heating issues. It originally had a bad idle and cold start problem along with an idle surge that turned out to be the idle control sensor and a vacumn leak. Once those where fixed it ran great with exception of the problem mentioned above. The next problem was a coolant leak at the timing chain cover. I had all the front and top end gaskets re-done which fixed that problem. A little over kill but due to the mileage I felt better safe than sorry.
So other than that I have just done regular maintenance on it. All the plugs and wires etc. where checked and are in great shape.
So I am stumped on this one and could use your help.
Finally, we finally had some cool weather here in Texas and I noticed that when I turned off my Air Conditioner the car seemed to have alot more power. Not just a little more power, but alot more power. It still struggled in lower rmps but seemed to perform better over all.
my 4.2 with a lift and heavy wheels and tires sturggles until about 2500-3000, then it gets into its powerband and accelerates. what gears do you have? most people, i believe including ford, say to replace all the electronics(coil pack, plugs, plug wires) at around 100,000. these engines are also notorious for vaccum leaks so you might have a new one. ill leave anything more techinical up to the other guys cause i haven had any problems with mine.
__________________ 2000 F-150 XL 2wd 4.2L, automatic
5.5" front 3" rear lift, 33" General Grabber AT2, Scangauge II(sig by Dirty88)
My truck is doing the same thing.. Here is what I posted.... My truck does the same thing at the light and when pulling. All the mechanics here think I am crazy, because the truck purrrss like a kitten when no trailer is behind it...
"I have a 97 f150 with a 4.2l in it. I use the truck to pull a trailer for a business. The truck runs good with no load. If I turn on the Ac I notice sometimes it seems like there is a big loss of power below the 2k range roughly. It feels like a elephant sits on the back of the truck and all the sudden jumps off because the power comes back instantly once the motor get up in the rpms more. The problem is even worse with the trailer behind the truck. For the first few miles its fine, but once I get a few good miles at 55 or better the problem shows its head when I try to take off from a stop of a slow turn. Sometimes when the trailer is behind it the truck will idle very rough and low too when sitting at a lite, but it has to be up to temp and driven a while for that to happen. The truck has had alot done in the last year. I have a new radiator, clutch, plugs (bosch platinum), wires, coil, and catalytic converters ( stock ones fell apart and clogged up). I also had to change a rubber elbow on the intake that goes to the back of the passanger side valve, because it was cracked and caused a lean engine code. The only other thing I notice is that the truck has had a smell of hot metal ever since the new catalytic converters were added. They told me it would go away its the oil burning off, but it hasn't in 2500 miles. So maybe my exhaust is clogged beyond the "Y" pipe? I have no other idea as to what my problem could be please help! I am tired of my local mechanic's throwing my money at a problem with no end result."
My truck is doing the same thing.. Here is what I posted.... My truck does the same thing at the light and when pulling. All the mechanics here think I am crazy, because the truck purrrss like a kitten when no trailer is behind it...
"I have a 97 f150 with a 4.2l in it. I use the truck to pull a trailer for a business. The truck runs good with no load. If I turn on the Ac I notice sometimes it seems like there is a big loss of power below the 2k range roughly. It feels like a elephant sits on the back of the truck and all the sudden jumps off because the power comes back instantly once the motor get up in the rpms more. The problem is even worse with the trailer behind the truck. For the first few miles its fine, but once I get a few good miles at 55 or better the problem shows its head when I try to take off from a stop of a slow turn. Sometimes when the trailer is behind it the truck will idle very rough and low too when sitting at a lite, but it has to be up to temp and driven a while for that to happen. The truck has had alot done in the last year. I have a new radiator, clutch, plugs (bosch platinum), wires, coil, and catalytic converters ( stock ones fell apart and clogged up). I also had to change a rubber elbow on the intake that goes to the back of the passanger side valve, because it was cracked and caused a lean engine code. The only other thing I notice is that the truck has had a smell of hot metal ever since the new catalytic converters were added. They told me it would go away its the oil burning off, but it hasn't in 2500 miles. So maybe my exhaust is clogged beyond the "Y" pipe? I have no other idea as to what my problem could be please help! I am tired of my local mechanic's throwing my money at a problem with no end result."
Theres your problem^^^^^^^
Too many people have had bad luck with running those plugs. Go buy cheap autolite plugs to see if it helps.
Autolites are even risky - but I don't think the V6 is as fussy as the V8's. You can't go wrong with the OEM Motorcrafts though.
no doubt dude cant go wrong with motorcraft
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Autolites are even risky - but I don't think the V6 is as fussy as the V8's. You can't go wrong with the OEM Motorcrafts though.
I only suggested them cause they are cheap, and if they don't fix his problem then he didn't waste to much on plugs. No body that I know that has the V6 and autolites have never had a problem with them, just have to change them more often.
dude, i bought 8 motorcraft plugs and a motorcraft oil filter for a 4.6 and it was only like 33 bucks, and the filter was almost 4 so motorcraft werent that expensive
Check for vacuum leak, then replace all vacuum lines and rubber elbows anyways cause it cost so little. Second time I have given this advice today, because when I did this for mine it was DRAMATICALLY DIFFERENT. If you already replaced the rubber elbow on back pass. intake, then check the one on bottom of egr valve. Well, replace ALL OF THEM, it is just too cheap not too. (My opinion of course that $20 is cheap) Also, replace upper plenum gasket, $15.
When was the last fuel filter changed? Could be your fuel pump mine crapped out right after I bought mine had all the same problems (except never pulled a trailer with it.)
Maybe check your TPS (throttle positioning sensor) as well, had a similar case last summer with mine sticking at inopportune moments...
As for the Bosch Platinum comments, I disagree as I put the +4's in both my 97 4.2 and my gf's 98 4.2 and to this day aside from the faulty plug there have been zero issues...
As for the Bosch Platinum comments, I disagree as I put the +4's in both my 97 4.2 and my gf's 98 4.2 and to this day aside from the faulty plug there have been zero issues...
Count yourself as one of the lucky ones.Put some in mine, ran so rough I thought the truck would shake itself apart.
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