Miss at startup
Freshman User
Joined: Mar 2005
Posts: 45
Likes: 0
From: near sacramento
ok my curiosity is peaked. i have the same problem on my 99, 4.0. and i sure think i've got it as tuned as posible.
the thing that helps usualy is the fuel injector cleaner. ya know that stuff you dump in the tank. i havn't done it for a while and the sputtering is getting bad agian. i'm anxous to hear if you all come up with somthing more profound that this.
the thing that helps usualy is the fuel injector cleaner. ya know that stuff you dump in the tank. i havn't done it for a while and the sputtering is getting bad agian. i'm anxous to hear if you all come up with somthing more profound that this.
Thread Starter
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New User
Joined: Feb 2005
Posts: 7
Likes: 0
From: WI
I still haven't completly solved the problem that started this thread, but I have found one thing. If I leave the key at "On" for ten seconds or so before starting, it does not miss. Why that bypasses the problem I don't know, but it works. If I jump in and just fire it up right away, I get the miss sometimes.
Mountain Pass
Joined: Aug 2003
Posts: 108
Likes: 2
I have the same problem on my 2000 4.0 4x4 S/Cab with 96K miles.
No CEL, no problems driving, but when starting and still in the (short) driveway, it misses while idling, and while just starting to roll forward or backward.
Once there's any amount of throttle applied, it's fine.
Haven't changed the fuel filter yet, and have only changed plugs once, about 60K.
Have changed the IAC valve last year, due to failure to idle when cold.
No CEL, no problems driving, but when starting and still in the (short) driveway, it misses while idling, and while just starting to roll forward or backward.
Once there's any amount of throttle applied, it's fine.
Haven't changed the fuel filter yet, and have only changed plugs once, about 60K.
Have changed the IAC valve last year, due to failure to idle when cold.
New User
Joined: Apr 2007
Posts: 7
Likes: 0
I have a 2000 with the same miss at startup. I have changed to upper and lower intake gaskets, the IAC, plugs, wires, fuel filter, MAF sensor, and my fuel pressure is at 60. I am thinking about the injectors but I am tired of throwing parts at this problem. I also do not have a CEL so no codes to read. If anyone has any other ideas I would love to hear it.
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
I have a 2000 with the same miss at startup. I have changed to upper and lower intake gaskets, the IAC, plugs, wires, fuel filter, MAF sensor, and my fuel pressure is at 60. I am thinking about the injectors but I am tired of throwing parts at this problem. I also do not have a CEL so no codes to read. If anyone has any other ideas I would love to hear it.
You might consider having a used oil analysis done to determine whether any coolant is mixing in with the oil. Cheap and easy to do: Blackstone Laboratories - Gas Engines
New User
Joined: Apr 2007
Posts: 7
Likes: 0
The interesting part is that the truck only runs rough for about 10-15 seconds and then the engine smooths out. I would think that a cracked or blown head gasket would take longer than that to seal up from building engine heat. Other than the rough starts fuel milage is ok and power is normal, if this problem were some serious engine wear or failure I would guess that I would see some performance issues. The truck has 102K on the original motor.
Senior User
Joined: Jan 2004
Posts: 130
Likes: 0
From: People's Republic of CA
Hello,
I have a 2000 Ranger, V6, 4.0L, 4x4. 90,000 miles.
I am having a problem at startup, with a miss. It only lasts for a few seconds, then everything seems fine. It also only does it on a cold start, not when the engine is warm. Basically, it runs really rough for a couple seconds, the RPMs are low by a couple hundred, then it catches and runs fine. It does it 9 out of 10 times if it is cold. After it starts running normal, everything seems good on acceleration and higher speeds. If I give it any gas while it is running rough, it doesn't help, just starts bucking faster.
Last week I got a check engine light, and it came back as a miss in cylinder 4. There was no noticeable miss at the time, and it hasn't come back on since it was reset. I assume it is from the same problem.
I have a 2000 Ranger, V6, 4.0L, 4x4. 90,000 miles.
I am having a problem at startup, with a miss. It only lasts for a few seconds, then everything seems fine. It also only does it on a cold start, not when the engine is warm. Basically, it runs really rough for a couple seconds, the RPMs are low by a couple hundred, then it catches and runs fine. It does it 9 out of 10 times if it is cold. After it starts running normal, everything seems good on acceleration and higher speeds. If I give it any gas while it is running rough, it doesn't help, just starts bucking faster.
Last week I got a check engine light, and it came back as a miss in cylinder 4. There was no noticeable miss at the time, and it hasn't come back on since it was reset. I assume it is from the same problem.
I've been having this same exact probem with my 98 4.0.
Changed the plugs at 100K. At 125K, bad miss from #4. Changed plug, perfect.
Now about every 4-5K the miss reappears. Fixed like new with a new plug on #4.
Kinda driving me nuts. Checked EGR, IAC, coil pack, wire, harness, etc. Also, problems with these or any other problems (head, gasket, IM or gasket, injector, fuel pump, etc. would NOT be immediately fixed by merely changing the plug. Have been using Motorcraft stock plugs. Plus there are no other misfires on any other cylinders. And, #4 plug is not fouled and otherwise does not appear to have anything wrong with it when removed. Even the ohm resistance is very close to a new plug.
I'm stumped, no logic to this. If anyone has any ideas, I'm all ears.
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Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
I've been having this same exact probem with my 98 4.0.
Changed the plugs at 100K. At 125K, bad miss from #4. Changed plug, perfect.
Now about every 4-5K the miss reappears. Fixed like new with a new plug on #4.
Kinda driving me nuts. Checked EGR, IAC, coil pack, wire, harness, etc. Also, problems with these or any other problems (head, gasket, IM or gasket, injector, fuel pump, etc. would NOT be immediately fixed by merely changing the plug. Have been using Motorcraft stock plugs. Plus there are no other misfires on any other cylinders. And, #4 plug is not fouled and otherwise does not appear to have anything wrong with it when removed. Even the ohm resistance is very close to a new plug.
I'm stumped, no logic to this. If anyone has any ideas, I'm all ears.
Changed the plugs at 100K. At 125K, bad miss from #4. Changed plug, perfect.
Now about every 4-5K the miss reappears. Fixed like new with a new plug on #4.
Kinda driving me nuts. Checked EGR, IAC, coil pack, wire, harness, etc. Also, problems with these or any other problems (head, gasket, IM or gasket, injector, fuel pump, etc. would NOT be immediately fixed by merely changing the plug. Have been using Motorcraft stock plugs. Plus there are no other misfires on any other cylinders. And, #4 plug is not fouled and otherwise does not appear to have anything wrong with it when removed. Even the ohm resistance is very close to a new plug.
I'm stumped, no logic to this. If anyone has any ideas, I'm all ears.
https://www.ford-trucks.com/forums/2...ke-gasket.html
As I noted above, a UOA is something that could help with the diagnosis.
Senior User
Joined: Jan 2004
Posts: 130
Likes: 0
From: People's Republic of CA
It could...anything's a possibility at this point.
Oil looks good, pretty clean even after 3K. No oil/ coolant mixing anywhere.
But, maybe I will try the analysis. What the hell, can't think of anything else to try.
But still, if it's a bad head/ gasket, a plug shouldn't do a damn thing, and the problem wouldn't go away and then return on a somewhat similar interval, know what I mean?
The problem almost seemed to me like this: a new plug had a lower resistance and as it aged, it developed a higher resistance until the ign system couldn't overcome the resistance anymore, leading to misfires. Kinda like the slow cranking with a good battery and old starter with higher internal resistance due to age or manifold heat problem/ scenario.
I dunno.
Oil looks good, pretty clean even after 3K. No oil/ coolant mixing anywhere.
But, maybe I will try the analysis. What the hell, can't think of anything else to try.
But still, if it's a bad head/ gasket, a plug shouldn't do a damn thing, and the problem wouldn't go away and then return on a somewhat similar interval, know what I mean?
The problem almost seemed to me like this: a new plug had a lower resistance and as it aged, it developed a higher resistance until the ign system couldn't overcome the resistance anymore, leading to misfires. Kinda like the slow cranking with a good battery and old starter with higher internal resistance due to age or manifold heat problem/ scenario.
I dunno.
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
I've been having this same exact probem with my 98 4.0.
Changed the plugs at 100K. At 125K, bad miss from #4. Changed plug, perfect.
Now about every 4-5K the miss reappears. Fixed like new with a new plug on #4.
Kinda driving me nuts. Checked EGR, IAC, coil pack, wire, harness, etc. Also, problems with these or any other problems (head, gasket, IM or gasket, injector, fuel pump, etc. would NOT be immediately fixed by merely changing the plug. Have been using Motorcraft stock plugs. Plus there are no other misfires on any other cylinders. And, #4 plug is not fouled and otherwise does not appear to have anything wrong with it when removed. Even the ohm resistance is very close to a new plug.
I'm stumped, no logic to this. If anyone has any ideas, I'm all ears.
Changed the plugs at 100K. At 125K, bad miss from #4. Changed plug, perfect.
Now about every 4-5K the miss reappears. Fixed like new with a new plug on #4.
Kinda driving me nuts. Checked EGR, IAC, coil pack, wire, harness, etc. Also, problems with these or any other problems (head, gasket, IM or gasket, injector, fuel pump, etc. would NOT be immediately fixed by merely changing the plug. Have been using Motorcraft stock plugs. Plus there are no other misfires on any other cylinders. And, #4 plug is not fouled and otherwise does not appear to have anything wrong with it when removed. Even the ohm resistance is very close to a new plug.
I'm stumped, no logic to this. If anyone has any ideas, I'm all ears.
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
Check it out: Ranger Used Oil Analysis
Senior User
Joined: Jan 2004
Posts: 130
Likes: 0
From: People's Republic of CA
Pawpaw- Yes, wires changed at 100K also.
Even tried a wire swap to rule out a bad wire, didn't help.
Rockledge- Well, I guess I'll try the analysis. From a purely logical point of view, I can't understand it, but if you experienced the same issue and found it thru analysis, then it certainly can't hurt to try one.
I'll get to it at some point and let you know what the results are.
Thanks for your time and all your posts to this site, you have an impressive knowledge base for the Rangers.
Even tried a wire swap to rule out a bad wire, didn't help.
Rockledge- Well, I guess I'll try the analysis. From a purely logical point of view, I can't understand it, but if you experienced the same issue and found it thru analysis, then it certainly can't hurt to try one.
I'll get to it at some point and let you know what the results are.
Thanks for your time and all your posts to this site, you have an impressive knowledge base for the Rangers.
