Need Help,engine started missing once it warms up.
11-14-2005, 11:56 AM
#21
3rd Gear Member
Join Date: Jan 2005
Location: Canton Ohio
Posts: 731
RE: Need Help,engine started missing once it warms up.
Ok your car runs fine at initial start up, but after a few minutes it runs like crap at the lower rpms. Once you hit higher rpms then that car runs better. I would have to say its either your o2 sensor, or possibly you coolant temp sensor. If I'm right you car ingnores most sensors until it begins to warm up to opporating temperature, so that could be why its fine when cold. A messed up o2 sensor will mess up your fuel comsumtion, a/f ratio, and make it run like straight poop. The same exact thing happened to me before i through a code. I would start there.
11-14-2005, 12:18 PM
#22
Moderating with Angels
Join Date: Jul 2003
Location: New Orleans La
Posts: 4,231
RE: Need Help,engine started missing once it warms up.
hey bro, i had that same issue with my 98gt/. couldnt figure it out myself tested the iac and the tps and both were fine on meter. took her into the shop and problem was resolve by replacing both the tps and the iac. go figure, was told both were bad and that did solve the problem . cheap fix
11-14-2005, 12:32 PM
#23
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
RE: Need Help,engine started missing once it warms up.
ORIGINAL: RodGT35th
Well guys I've heard of the intake recall issue and the thought of cracked manifold has crossed my mind. I looked that engine all over today, dry as a bone.
Tell me, a slipping clutch would slip when cold too right? The motor sounds fine when in neutral and revving. It's only when at low RPM under load when warm is it an issue. The lower the RPM and higher load such as an uphill grade is when you feel the most. In fact I even went out on some side streets and started off in second. Really bad then until you get up past 2500 to 3000 RPM then fairly skip free. I guess it's dealership time. Dang it I pride myself on figuring stuff out and not going there. I know they over charge for everything. Looks like this one might be over my head. You know I believe the auto makers want it to be more and more difficult to diagnose problems. I've got a 62 Ford Galaxie(my first car by the way, had it since 1984)with a 352 FE big block. Man that things a piece a cake to fix. Look at image attached of my rides:-)
Well guys I've heard of the intake recall issue and the thought of cracked manifold has crossed my mind. I looked that engine all over today, dry as a bone.
Tell me, a slipping clutch would slip when cold too right? The motor sounds fine when in neutral and revving. It's only when at low RPM under load when warm is it an issue. The lower the RPM and higher load such as an uphill grade is when you feel the most. In fact I even went out on some side streets and started off in second. Really bad then until you get up past 2500 to 3000 RPM then fairly skip free. I guess it's dealership time. Dang it I pride myself on figuring stuff out and not going there. I know they over charge for everything. Looks like this one might be over my head. You know I believe the auto makers want it to be more and more difficult to diagnose problems. I've got a 62 Ford Galaxie(my first car by the way, had it since 1984)with a 352 FE big block. Man that things a piece a cake to fix. Look at image attached of my rides:-)
It's the easiest and cheapest thing to check. As heat causes expansion, the crack in the plug could be big enough (when warm) to cause voltage leaking. (blue lightening at the plug that is bad) Under a load would make sense since a higher voltage spark is used under loads.
Idle Air Control (IAC) is just for idle, nothing more. What you are describing has nothing to do with Idle.
Throttle position sensor (TPS) would generally cause that issue at high rev regardless of load. So although I wouldn't say that's the cause, I wouldn't quite rule that out.
Mass Air Flow (MAF) may be a culprit but if you already checked it, I would rule it out for now.
Plugs...
11-14-2005, 01:25 PM
#24
Thread Starter
Join Date: Jan 2004
Location: United States
Posts: 33
RE: Need Help,engine started missing once it warms up.
I am beginning to think maybe it's the O2 sensor myself. As far as the computer ignoring readings until engine is warm. Thats what the Chiltons book said too. So I beleive that almost would narrow it down to O2 sensor. At least as far O2 vs. temp sensor being the culprit. Because the computer is obviously sensing the warm up. I called a mechanic that I prefer over the dealership this morning. He says to bring it by tommorrow. Says he can get a little more info than a std code reader can. Thanks to everyone for all your consideration. I will promptly post when and if I get a solution.
11-14-2005, 06:49 PM
#25
3rd Gear Member
Join Date: Apr 2005
Posts: 607
RE: Need Help,engine started missing once it warms up.
Let us know...O2 sensors almost always bring on a light, while it is common for misfires to not.
Like Derf said...ignition problems usually show up hot due to thermal expansion. A coolant temperature sensor is a possibility. On the distributorless ignitions systems...misfires usually show up at low rpms under a load. A good drivability tech that knows the Ford diagnostic machine will actually check for misfires with the parking brake on and the vehicle in reverse, throttle at 1200-1500 rpm (controlled by the machine).
My wager is on cylinder #3 or #7
Like Derf said...ignition problems usually show up hot due to thermal expansion. A coolant temperature sensor is a possibility. On the distributorless ignitions systems...misfires usually show up at low rpms under a load. A good drivability tech that knows the Ford diagnostic machine will actually check for misfires with the parking brake on and the vehicle in reverse, throttle at 1200-1500 rpm (controlled by the machine).
My wager is on cylinder #3 or #7
11-17-2005, 03:48 PM
#26
Thread Starter
Join Date: Jan 2004
Location: United States
Posts: 33
RE: Need Help,engine started missing once it warms up.
Well ya'll, I got the diagnosis today. Bad #3 COP (coil over plug). Just got off the phone with the shop. I didn't get a chance to talk directly to the mechanic yet to see how he come to his finding. The shop secretary said that they replaced the coil and plug and voila...fixed. When I find out his method of determining that I will post as I believe it could help us all again someday. total repair with tax...$158.59. Thanks to everyone who posted their advice. This is an awesome website.
11-18-2005, 10:22 AM
#28
Thread Starter
Join Date: Jan 2004
Location: United States
Posts: 33
RE: Need Help,engine started missing once it warms up.
JGlisson, EXCELLENT CALL! What led you to your guess of #3 or #7 cylinder? That was great forsight man. My mechanic said he ended up hooking to his diagnostic machine. It was showing week ignition on #3. So he ohmed out the secondary and found it. He said it happens quite a bit on COP. Next time I'll know what to look for. PLUS I'll go to the salvage yard and buy repalcement COP. $97.00 each Ouch. Anyways, a big Blue Oval salute to your diagnostic skill.[sm=usa.gif]
Rod
Rod
11-18-2005, 03:12 PM
#29
2nd Gear Member
Join Date: Apr 2005
Location:
Posts: 222
RE: Need Help,engine started missing once it warms up.
Sounds like Spark Knock to me, which is your fuel is not igniting fast enough causing piston slap which is bad. go lower octane gas thats what they call for 4.6 stangs they dont have high compression so all u need is 87 octane. Try that and some fuel injector cleaner and see how it does.
11-18-2005, 03:34 PM
#30
Thread Starter
Join Date: Jan 2004
Location: United States
Posts: 33
RE: Need Help,engine started missing once it warms up.
Hey black01GT, thanks for replying. The problem actually was #3 COP (coil over plug) gone bad. See my last post.Car is running great now.
In reference to spark knock or detonation. You would actually increase octane levels if you were trying to remedy that type of situation. Using 89 or even 93 should help deter detonation. If I'm not mistaken and correct me people if I'm wrong. Octane raises the "flash point" of the fuel. This keeps the fuel or rather helps the fuel not to ignite because of cylinder hot spots or ....higher compression(dieseling).
Rod
In reference to spark knock or detonation. You would actually increase octane levels if you were trying to remedy that type of situation. Using 89 or even 93 should help deter detonation. If I'm not mistaken and correct me people if I'm wrong. Octane raises the "flash point" of the fuel. This keeps the fuel or rather helps the fuel not to ignite because of cylinder hot spots or ....higher compression(dieseling).
Rod
