Engine/Transmission Missing problem - Off-Road Forums & Discussion Groups
Ford 67-96 F-Series, 78-96 Bronco All discussions of 67-96 F-Series Trucks and 78-96 Broncos

Reply
 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 01-14-2001, 02:47 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Engine/Transmission Missing problem

Iím having a problem diagnosing a missing issue and need some advice. I have a 1991 Bronco with a 351 EFI engine and auto 4 speed with OD on the dash with about 72,000 miles. When Iím driving at speeds around 35 mph or more and then let up on the gas to slow down a bit, when I press the gas pedal again, I get what appears to be a hard engine miss. Usually just one, but sometimes two. After that the Bronco accelerates just fine. It ideals great, runs strong, only this one issue.

I brought it in to a carb shop and they put in a new EGR valve and gate, they also vacuumed out the intake system. They checked everything possible and said itís perfect. When I got it back the miss is somewhat improved but still there. Does anyone have any idea what could be? Could it be the transmission causing this miss felling?

Thanks


Sponsored Links
Advertisement
 
post #2 of (permalink) Old 01-14-2001, 05:48 PM
Mud in my Veins
 
Steve83's Avatar
 
Join Date: Dec 2000
Location: Memphis, TN
Posts: 5,301
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Engine/Transmission Missing problem

My truck did that exact same thing a few months ago and it turned out I hadn't changed the spark plugs in about 80Kmi. The gaps were a consistent .14".

(The transmission can't cause a miss.)

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15
Steve83 is offline  
post #3 of (permalink) Old 01-14-2001, 06:44 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine/Transmission Missing problem

I changed the plugs about 5K miles ago. The strange part about it is it only does it when I fist hit the gas. After that it's ok. I wonder if I have a weak plug. Feels like it's a bigger miss than one plug.

Sponsored Links
Advertisement
 
post #4 of (permalink) Old 01-14-2001, 07:11 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine/Transmission Missing problem

How are your wires. If they're carbon core, they may be degraded enough to cause your problem. They are also brittle enough (carbon core wires) to crack internally if they get kinked.

post #5 of (permalink) Old 01-14-2001, 10:10 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine/Transmission Missing problem

I have the original carbon wires replaced about 15K miles ago with wire core wires. The strange part about this is the Carb shop put the engine on a meter and check the plugs and wires and said they were in good shape. The engine runs great expect this one miss on initial acceloration.

post #6 of (permalink) Old 01-14-2001, 11:12 PM
Mud in my Veins
 
Steve83's Avatar
 
Join Date: Dec 2000
Location: Memphis, TN
Posts: 5,301
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Engine Missing

Pull the codes - the computer should have noticed this if it's coming from the engine. Also, check the timing, the cap & rotor, and the rear diff for metal flakes in the oil. It may be the pinion striking the carrier if the pinion nut is loose.

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15
Steve83 is offline  
post #7 of (permalink) Old 01-14-2001, 11:34 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine Missing

Good points. The computer codes are clear. I was thinking it might be the torque converter slipping before it locks up, since it happens when I'm decelerating and then accelerate again. I have ARB air lockers in the rear and front with manual hubs. I've always been suspicious of the transmission, as it seems go bog down before down shifting. A couple of years ago a transmission shop told me to change the computer from the 91 stock unit to a stock 93 unit. That it was a known problem. Seems to help the bogging a bit, but still not a good as I think it should be. The guy that does my transmission work is next door to the person that installed the ARBís. Sounds like I might visit both. Thanks for your advice.

post #8 of (permalink) Old 01-15-2001, 01:27 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine Missing

hey bobang,
Whaddya think of yer arb's????? Would u install them all over again? Have u had any probs with leakage? How much did it cost for labor on the install? Are ya happy with em?
-mike

post #9 of (permalink) Old 01-15-2001, 10:36 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Engine Missing

I love the ARBís. There are two main reasons I installed them. For pulling out a ski boat from a steep lake bed and for driving in deep snow and pulling my snowmobile trailer. I tried clutch type of differentials and they just didnít give me the control I wanted for slow speed all-wheel drive. The one thing I did do different was rewire the locking switches so I and lock the front and rear independent of each other. Havenít has a single problem with leaking and they have been on for 4 years. Not sure what I paid for them but at the same time I changed the front and rear gears to 4:25. They are pricey but if you need them for slow speed maneuvering you canít beat them. There are many times when driving in deep snow Iíll lock the front and not the rear.

post #10 of (permalink) Old 01-19-2001, 03:24 PM
Mud in my Veins
 
Steve83's Avatar
 
Join Date: Dec 2000
Location: Memphis, TN
Posts: 5,301
Thanks: 0
Thanked 0 Times in 0 Posts
 
Have you found it yet?

What did it turn out to be?

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15
Steve83 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome