miss then no miss

Just me · 11-16-2002, 04:31 PM

Hows it going? Ok when my car is cold it idles ok but feels like its missing a cylinder under any acceleration, then all of a sudden it'll kick in and run smooth. After a few minutes it will miss again. I reset the computer and ran the KOEO test. All it told me is that the car was too lean so I adjusted my fuel pressure and still had the same problem. When I ran the test again it told me it was too rich. DOH! I adjusted the pressure again and the puter liked it this time but I still have the problem. The car misses one minute and then runs strong the next. Very unpredictable and hard to solve. I've changed a number of things to no avail. Any suggestions? Oh, I did notice the fuel pressure needle pulses.
Thanks in advance.

Just me · 11-16-2002, 04:33 PM

I forgot to mention I have a 91 LX.

jayinpa · 11-16-2002, 05:16 PM

I had a problem like that with my 88gt. I found that the coil was bad. When it would mess up, it would cause a rich condition due to not fireing all cylinders good, so the cpu would compensate for it by leaning out the engine. But then the coil would start working again and the cpu would find a lean condition. This cycle would happen over and over. Changed coil and problem went away. I hope this helps.

JAY

Just me · 11-16-2002, 06:24 PM

Thanks. I bought a new MSD coil and 6A ignition about a year ago because my Jacobs would cut off the engine in mid flight. I wonder if your right, if this is a similar problem. I did pull all of my plugs and they all looked clean no carbon except for one. This one plug was wet with fuel. Hmm. After I cleaned it, I checked it a couple of days later and it was fine. I'm going to find another coil to test. Thanks again

fred50stang · 11-16-2002, 08:43 PM

I had a problem that was about the same, and after trouble shooting I found that one of my injectors was stuck. The plug for that cyl. was black, so I swapped out inj to see if the problem followed and it did.
So my suggestion is the cylinder that ran rich try swapping out that inj with another one and see if the problem follows. One other problem was the the stock fuel press. reg. had blown also. So you might need to check the fuel pressure.
- Hope this helps.

Just me · 11-17-2002, 04:39 AM

Thanks. The plug that I pulled wasn't black,just wet. Maybe there wasn't enough time to turn black before I pulled it. I don't have a stock FPR, I have a Areomotive billet adj FPR. I'll swap out that injector to see if thats the deal. What about the distributor module? What does that do when it goes bad? If it helps, here's what I got mostly 2 years ago. Thanks again.

91'lx, 302 block, crank pulley, no smog, short belt, Wolverine 1087 cam, 15 deg timing, TFS TW heads, motorsport 1.6 3/8 stud RR, ARP studs, TFS chrome hardened push rods, 24lb inj, BBK 255lph fuel pump, Areomotive billet adj FPR, Performer RPM intake(ported to 75mm), 1" spacer, Motorsport polished tall valve covers(love em), Pro-M 77, Acufab 75mm TB, Ford idle air bypass valve, K&N conical, MSD 6AL and coil, 9mm MS cables, NGK bkr5e 11 plugs@55, motorsport 3 core radiator,160 thermostat, Hurst short throw, motorsport 410 gears, aluminum drive shaft,Kenny brown Subs, Mac 1 3/4"Long tube, custom 3"off road xpipe, 2 chamber Flow Masters, 3 1/2" tailpipes HAL tubular K-member, KYB struts and shocks, Eibach springs, Steeda 2.5" Cowl, Steeda rear wing, black Dupont centari acrylic enamel paint.

fred50stang · 11-17-2002, 10:37 AM

You can pull that TFI module off the front of the distributor and have it tested at a local parts store, I know advance auto parts has a tester, and I think its a 5.5mm bolt in there and its kind of a b**ch to get to you have to use a special tool. I would say that if your fuel press. reg was blown you would get horrible mileage. My stock one blew and that his how I noticed that.

Just me · 11-17-2002, 02:43 PM

Thanks. I have a 90 degree socket driver for things like those nasty little modules and I also have a hammer to bash them into next year lol. I get pretty crappy fuel mileage with all of my mods but I don't know how crappy it should be. I should of listened to my friend's advice when he told me to put on on e part at a time to see what advantages and disadvantages I get from each part but I wouldn't of felt the huge kick in the *** from everything together. I should of modified a new car he he.

11-16-2002, 04:31 PM	#1
Just me Registered Member Join Date: Nov 1998 Location: Miami,Florida Posts: 159	miss then no miss Hows it going? Ok when my car is cold it idles ok but feels like its missing a cylinder under any acceleration, then all of a sudden it'll kick in and run smooth. After a few minutes it will miss again. I reset the computer and ran the KOEO test. All it told me is that the car was too lean so I adjusted my fuel pressure and still had the same problem. When I ran the test again it told me it was too rich. DOH! I adjusted the pressure again and the puter liked it this time but I still have the problem. The car misses one minute and then runs strong the next. Very unpredictable and hard to solve. I've changed a number of things to no avail. Any suggestions? Oh, I did notice the fuel pressure needle pulses. Thanks in advance.

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11-16-2002, 04:33 PM	#2
Just me Registered Member Join Date: Nov 1998 Location: Miami,Florida Posts: 159	I forgot to mention I have a 91 LX.

11-16-2002, 05:16 PM	#3
jayinpa Registered Member Join Date: Jan 1999 Location: Greensburg,PA Posts: 75	I had a problem like that with my 88gt. I found that the coil was bad. When it would mess up, it would cause a rich condition due to not fireing all cylinders good, so the cpu would compensate for it by leaning out the engine. But then the coil would start working again and the cpu would find a lean condition. This cycle would happen over and over. Changed coil and problem went away. I hope this helps. JAY

11-16-2002, 06:24 PM	#4
Just me Registered Member Join Date: Nov 1998 Location: Miami,Florida Posts: 159	Thanks. I bought a new MSD coil and 6A ignition about a year ago because my Jacobs would cut off the engine in mid flight. I wonder if your right, if this is a similar problem. I did pull all of my plugs and they all looked clean no carbon except for one. This one plug was wet with fuel. Hmm. After I cleaned it, I checked it a couple of days later and it was fine. I'm going to find another coil to test. Thanks again

11-16-2002, 08:43 PM	#5
fred50stang Registered Member Join Date: Apr 2000 Location: E-city, nc Posts: 24	I had a problem that was about the same, and after trouble shooting I found that one of my injectors was stuck. The plug for that cyl. was black, so I swapped out inj to see if the problem followed and it did. So my suggestion is the cylinder that ran rich try swapping out that inj with another one and see if the problem follows. One other problem was the the stock fuel press. reg. had blown also. So you might need to check the fuel pressure. - Hope this helps.

11-17-2002, 04:39 AM	#6
Just me Registered Member Join Date: Nov 1998 Location: Miami,Florida Posts: 159	Thanks. The plug that I pulled wasn't black,just wet. Maybe there wasn't enough time to turn black before I pulled it. I don't have a stock FPR, I have a Areomotive billet adj FPR. I'll swap out that injector to see if thats the deal. What about the distributor module? What does that do when it goes bad? If it helps, here's what I got mostly 2 years ago. Thanks again. 91'lx, 302 block, crank pulley, no smog, short belt, Wolverine 1087 cam, 15 deg timing, TFS TW heads, motorsport 1.6 3/8 stud RR, ARP studs, TFS chrome hardened push rods, 24lb inj, BBK 255lph fuel pump, Areomotive billet adj FPR, Performer RPM intake(ported to 75mm), 1" spacer, Motorsport polished tall valve covers(love em), Pro-M 77, Acufab 75mm TB, Ford idle air bypass valve, K&N conical, MSD 6AL and coil, 9mm MS cables, NGK bkr5e 11 plugs@55, motorsport 3 core radiator,160 thermostat, Hurst short throw, motorsport 410 gears, aluminum drive shaft,Kenny brown Subs, Mac 1 3/4"Long tube, custom 3"off road xpipe, 2 chamber Flow Masters, 3 1/2" tailpipes HAL tubular K-member, KYB struts and shocks, Eibach springs, Steeda 2.5" Cowl, Steeda rear wing, black Dupont centari acrylic enamel paint.

11-17-2002, 10:37 AM	#7
fred50stang Registered Member Join Date: Apr 2000 Location: E-city, nc Posts: 24	You can pull that TFI module off the front of the distributor and have it tested at a local parts store, I know advance auto parts has a tester, and I think its a 5.5mm bolt in there and its kind of a b**ch to get to you have to use a special tool. I would say that if your fuel press. reg was blown you would get horrible mileage. My stock one blew and that his how I noticed that.

11-17-2002, 02:43 PM	#8
Just me Registered Member Join Date: Nov 1998 Location: Miami,Florida Posts: 159	Thanks. I have a 90 degree socket driver for things like those nasty little modules and I also have a hammer to bash them into next year lol. I get pretty crappy fuel mileage with all of my mods but I don't know how crappy it should be. I should of listened to my friend's advice when he told me to put on on e part at a time to see what advantages and disadvantages I get from each part but I wouldn't of felt the huge kick in the *** from everything together. I should of modified a new car he he.