Ford F-150 - 1997-2003 :: 4.2L - Suddenly Started Missing Under Load
Apr 26, 2012
My 4.2 liter F150 suddenly started missing under load. A little background: It is a late 2003 and has 75k miles. It has been in my family since new, and I have had it for the last 4 years. This truck is as stock as they come, and has been well maintained.
On my way to work yesterday, it began missing. Not bad at first, but got worse. It misses while under load and under acceleration. The "check engine light" never came on. I have not put fuel in in several days, and it ran fine until now, so I doubt it is bad fuel. I started the engine after dark and looked for arcing. None visible, and I even sprayed the wires with a mist of water. I pulled the plugs and they all look normal. The gaps were all way too large, so I regapped the plugs to .054". I pulled the coil pack and it checks within range with my VOM. Can the coil pack be the problem even though it checks out on the bench? Can the large plug gaps have contributed to a coil pack failure?
Where to start. I HATE just throwing parts at this thing, and I don't like wasting money... If I let one of the auto parts stores run a scan, will it show a code even though I have no check engine light? I used to think of myself as a pretty good diagnostician, but then again, when I used to spend a lot of time under the hood, those cars had points, condensers and carburetors...
View 4 Replies
Advertisement
Have a p0401 code which I need to diagnose and solve. However, I don't believe the symptoms are indicative of the EGR system. Its a 1999 4.6L auto approximately 200k miles. Truck runs fine until it warms up, and then occasionally it begins to act like its missing under load. steady state on the freeway it may have an occasional miss, but put a load on the motor and the miss becomes real bad. This doesn't seem to me to be symptomatic of a P0401 code, but I don't really understand the EGR system enough to be sure. Searching on the forums for other p0401 codes doesn't seem to have the same symptoms.
View 10 Replies
I've got a 97 f150 4.6 that has randomly started missing over the last month. It has started to get more frequent and codes are showing a misfire on both cylinder 1 and 8. Both of these cylinders run off the same coil pack. I'm thinking its the coil? The plugs and wires, motocraft, have about 3k on them and the truck runs great otherwise. I just don't know how common a coil would cause this or if they would act intermittent like this.
View 5 Replies
I have an 1999 f150 4.2l only 82,000 original miles.i have had truck since new .i just replaced the spark plugs for the first time.i used autolite plat. I also changed fuel filter the truck started to run like crap now shaking and sorta like missing.i pulled the plugs again rechecked the gp reinstalled them installed new wires still runs like crap.went out bought new motorcraft plat. plugs gapped at .054 still runs like crap..so i checked the gap on original plus that have been i the truck since new the gap on them are .074-.075. should i try and gapp the new ones to this the truck ran like a dream with the original plugs at this gap????
View 14 Replies
I have a 2000 f150 with 5.4 Triton with 165k miles. I did invest in a code reader. It started missing and code P0302 came up along with P0171. Put new coil on #2 and truck ran fine for a few days. Then it started to run rough again. Shaking, Idle rough, no power and CEL came on again. This time code P0171. I changed out fuel filter to no avail. My next step was to start looking for vacuum leaks. As I'm searching, All I am finding is trucks with this problem also get P0174 code. My question is since I am only getting lean on one bank does that pretty much eliminate things like MAF or the famous elbow vacuum leak and make something that only affects one bank like an O2 sensor on CAT more likely?
View 2 Replies
I have a 2001 F150 4.6L auto. This truck suddenly started running rough. Cleared all codes and re-scanned after starting truck. The codes are as follows; P0135, P0155, P0443, P0740, P0743, P0758, P1451, P1460, P1747, and P1760.
My question is; is it normal to have this many DTCs come up at once? Could my PCM be faulty causing this problem? Can you swap a pcm from the same year truck with the same options without reprogramming?
View 2 Replies
I purchased an '03 V10 Excursion back in '13 with about 145000 miles on it. I've added another 30,000 in the last year and a half. It's been good but has started missing and has gotten to the point where it will shut off at times and I don't know how to troubleshoot it. The MIL has never lit from the missing. Twice after it cut off the MIL was lit with a speed sensor error.
I've purchased a BAFX Products Bluetooth OBD2 interface and I've tried a couple of different Android apps with it, right now I'm using Torque Pro. It says it's an OBD I system which I saw references to in the "Why your MIL doesn't turn on" thread. I'm seen references to using Mode 6, but everything I've read seems to indicate that's an OBD II feature.
The missing gets better and worse. Some days it will seem to be fine and then other days I have to keep it rev'ed up to keep it from dying while stopping for a red light.
When it dies, it dies while stopped in drive or reverse. It has also died a couple of times while moving in reverse while connected to a 3,500lb trailer. Every time it's died it has started right back up.
View 10 Replies
1994 f250 7.3 turbo problem.. runs great on the level.. Cruises 65 no problem.. We have an 8% grade coming from town and half way up it starts cutting out and sounds like a jack brake under the hood and loses power.. Once over the top it clears out and runs fine again.... I just changed the fuel filters but no luck... I have been wrenching on cars all my life but no diesels..
View 6 Replies
I have been puzzled to why my truck isn't running right. We were driving down the highway one day and*then all of the sudden it starts running really rough. I changed MAF sensor, plugs and plug wires, oil change, fuel filter and air filter. Still doing the same thing. What this could be? 2003 ford sport trac..
View 11 Replies
I have an 01 SuperCrew with the 4.6L and it's idling really rough. Last summer, the idle started to flux pretty bad with the a/c on and eventually, it started to spray coolant mix through the vents and I lost heating about the same time. So, local dealership changed out the heater core and that is working again.
Well...I still have the idle flux, it fluxes from between 400-1000rpm at idle with the a/c on, it's a constant flux....up/down/up/down/up/down. A/C off and the idle is rock-solid steady. Dealership has changed 4 ignition coils over the last couple of years along with an EGR or PCV (whatever it's called) valve as well, none of which was for the idle problem, but somewhat associated. Where I should be looking?
View 2 Replies
A friend from work is having what he says is piston slap, but only under a load. I feel it could be the timing set since it's never been changed and at least 160k miles. Odometer quit working at least 5 years ago. Other than that, motor runs great. 1997 F150 4.6....
View 4 Replies
it's missing at an idle and it acts like it dont wanna take gas but once you get it going on the road it does good. the motor is a remanufacture motor it's only got 6,000 miles, new coils, plugs and wires, cam sensor, crank sensor, idle air control, mass air flow,and temp switch.
View 9 Replies
So today, I planned on switching the belt, idler pulley and tensioner since at least two of them are making noises. After taking all of the stuff off, belt, idler pulley and tensioner... and since I always compare parts I buy to parts that were in, making sure they are identical and I didn't order the wrong one. So first up I checked my tensioner and the position of them or angles are different, completely different.
So Google it to view a few diagrams and bang! it hits me... the one I took out from my F150 is for a non-AC... so back into the truck and I'm looking. Didn't have to go far when I realized that my AC compressor is missing!!!!
I keep looking around and I see that yes, I did have AC in it before I got it; because the guts are there but sliced! Great, so the job went from easy and easy I mean buy compressor and install; but now since the guts were cut, the PO sliced the thing out simply put.
1.) What are the bolt sizes that hold the compressor in place?
2.) Is there a wire connector on the compressor? or no?
View 1 Replies
It has been since the 80's that I have attempted to do any work on a vehicle. How do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents. I have an 2000 F150 with the large engine with about 112,000 miles.
View 11 Replies
1999 4.6 (106K miles) will stumble / miss when at 35-50 mph under a mid throttle load (just before reaching the downshift point). Has been doing this since I bought the truck at 70K miles.
Computer has no codes, engine runs fine under all other circumstances, and gets a decent ~20 MPG on the highway.
Done the standard tune up items (plugs / motocraft) and cleaned MAF, replaced TPS, tranny flush/ filter. Replaced the left O2 sensor 2 months ago, but it dumped a code and was really noticeable when it went out.
I am about ready to dive off and replace the MAF, but at $100 a shot would like other alternatives to try first. I am really convinced the engine is leaning out and misfiring under this load.
View 14 Replies
I have 2001 F-150 with 4.6L. Truck runs fine until under load and runs fine until I slow down to a stop sign. Once truck sits for a few moments it fires up again and will run for a short while then will do it again. Each time i let it sit for a few minutes, it will start again.
I pull a small travel trailer and seems to happen more frequently when pulling or climbing hill, but not under full power, just when slowing down. Could this be cause of catalytic converters? MAF sensor, or fuel starving.
Check engine light is on, will codes identify if it is a plugged cat?
View 6 Replies
My daughter has a 2010 F150 with 5.4, when pulling her horse trailer or extended idling her truck starts running rough, so far her husband has changed the fuel pump and 2 coil packs, no luck.
View 3 Replies
I have a 03 f150 2wd with the 4.6l. Recently it has been slow shifting into reverse(about 2 full seconds) and when it finally gets in reverse it shudders when it comes under load. The fluid is full and not burnt...
View 1 Replies
I've got a 97 truck, broke the crank, swapped in a motor from an 07. Heads down is 07, intake up is 97. had heads planed and a valve job with new seals done. Left it alone from the rings down. Got it in this weekend, running today. Ran it in the driveway with no load for about 30 minutes, top end was noisy for about 5 minutes till the top end got good and oily (I'm assuming). Purred like a kitten, sounded real smooth. Took it for a drive around the block, heard the clatter in the video below. It's almost always there when driving. Brought it back, turned it off to check oil, it was a quart low. Added oil, startup was VERY labored with a real hard knock in the bottom end. Ran like poo till I gave it some throttle for a couple seconds, then it cleaned up and idled well. Let it run for a couple minutes, turned off and let it sit for a couple minutes then started back up, same thing. Very labored with hard knocking.
View 2 Replies
I have a 2002 Ford F-150 with a 5.4 Triton. 212,xxx miles. I replaced the cops and the plugs about 6 months ago. I was pulling a trailer up hill last week and the engine was under a load doing about 3000rpm. It began to misfire and give me a flashing mil. However, before I went very far the engine began to run fine. It happened 3-4 different times. However, there is no code recorded. I've driven the truck nearly 100 miles with no problems, but I'm going to be pulling that trailer uphill again next week.
View 8 Replies
I recently bought a 2000 f150 4.6 with 105000 on it I notice when I was driving if the engine got under a load it whined. It does it every time and it does it being parked but not as bad. What it could be?
View 2 Replies
