1992 F-150 Top End Misfire - Ford F150 Forum - Community of Ford Truck Fans

Topic Sponsor

1992 F-150 Top End Misfire

Reply

 
 
 
Old 04-17-2017, 09:05 AM
  #1  
Junior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Default 1992 F-150 Top End Misfire

I am a little new to posting on forums, I hope I am doing this right.
I recently did a tune up.
I replaced the following items:
Spark Plugs
Spark Plug wires
Distributor Cap and button
Oil and filter (10-W30)
Rear Fuel pump
Belt
tensionor pulley

Before I did the tune-up, she was not running bad. She had a misfire every now and then. The rear tank fuel pump was weak, now since the replacement, the rear tank works flawless. Idle was good, top end power was good.

The problem I am having since the tune-up is, she has a nasty top end misfire. At 60 or 65, when i ascend an incline, she starts to misfire really bad. So bad in fact, it jerks the entire truck. My knowledge of the way this truck works is amateur at best. I suspect that I may have cracked the white insulation on one of the spark plugs is the issue. She still idles well (seemingly better than before the tune up).

What I would like to find out is, if the misfire still happens after the spark plug replacement, where would I start next as far as solving the misfire?

Thanks.
redleg122 is offline  
Reply With Quote
Old 04-18-2017, 09:03 AM
  #2  
Member
 
Join Date: Feb 2016
Location: Council Bluffs, Iowa
Posts: 35
Thanked 0 Times in 0 Posts
Default

I would suggest a clogged catalytic converter. But I don't know how you could verify that w/o just changing it.
Myron's is offline  
Reply With Quote
Old 04-20-2017, 06:29 AM
  #3  
Junior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Originally Posted by Myron's View Post
I would suggest a clogged catalytic converter. But I don't know how you could verify that w/o just changing it.
Thanks for the input. I did consider the clogged cataylic converter and the fuel filter. I changed the fuel filter. It still had the misfire. Then I took it to the shop, the mechanic told me that when i replaced the spark plugs, I cracked the spark plug on cylinder 5. I also found out the my truck has a straight pipe?
redleg122 is offline  
Reply With Quote
Old 04-21-2017, 10:09 AM
  #4  
Senior Member
iTrader: (1)
 
Chris_1's Avatar
 
Join Date: Mar 2014
Location: Ontario, Canada
Posts: 5,724
Thanked 682 Times in 647 Posts
Default

You don't say what motor you have but cylinder 5 is easy enough to get to on either a v8 or a 6.
A cracked plug would do that.
If that doesn't work, get a gauge and test the fuel pressure. A new pump doesn't guarantee good pressure.
Chris_1 is online now  
Reply With Quote
 
 
 


Thread Tools
Search this Thread

Contact Us Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: