I have been having intermittent problems with the 5.0 in my 88 F-150 for a couple of months now, and never seem to be able to pinpoint the problem. I have checked to see if the itake gaskets are leaking, (used carb cleaner and sprayed around the base of the upper, lower, and throttle body) cannot find a leak anywhere. I have checked all of my vacuum hoses, and even replaced the pcv, pulled the K&N and put a paper filter back in, and changed out the breather filter. All to no avail. This is really starting to drive me nuts.

The only time the truck backfires is when it's cold, and I give it some gas. It will try to die out, then pick back up and backfire through the exhaust. I also have a severe lack of power around 1200 to 2000 rpm. It's like it's stumblimg trying to run.

I am starting to wonder about the timing. I pulled the distributor about 5 months back to replace it (seals went bad, oil was getting up to the top of the distributor). I got the timing right on, 10 BTDC with the spout disconnected. Is there anyway this could've gotten off in this amount of time?

I just put a new heav duty (double roller) chain in in October of 99.

Any help is greatly appreciated.




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If its backfiring back thru the intake then Id suspect you have a valve(s) problem . Since the timing chain is reletively new there shouldnt be enough wear to allow the valve timing to be off allowing it to backfire .

 

Could it be running lean? I ask this because after replacing my injectors with higher #'age units I had this really cool *popping* sound whenever I engine braked or rev'd, just a thought, I purchased an adjestable fuel regulator and tweaked it a little bit and the popping went away. I kinda liked the sound it made as I engine braked in 2nd gear from 30mph to a stop light, hehe

1995 F-150XL SC/SB
http://members.sounddomain.com/blind
5-Star Rated F-150 (Big Stereo)

 

Hotrod, Check you ignition wiring. The wire harness to the distributor and around the module. I have had these wires ware on the frame from vibration and actually start to short out. It is almost like turning the key on and off while going down the road. I repaired the wires and cleared up the backfire. Just a thought. Good luck.

Jakegypsum // Ford fleet, soup to nuts.

 

It's possible you could have a lobe going flat on your cam If it's back firing through the intake.

 

Guys,

I hate to say this but it's not backfiring through the intake. It's backifiring through the exhaust, but it's not like your normal exhaust backfire. I only hear it from right around the headers, basically in the area of where the header's / cats are.

This is not a constant problem, only when it's really cold.

Thanks for the help, I really appreciate it. I will be coming here more often in the near future, as I just picked up a great little 65 F-100 short wheelbase.


[link:www.geocities.com/hotrodford_88/|Hotrodford_88's Webpage]

[link:www.geocities.com/hotrodford_88/1965_F100.html|Hotrodford_88's 1965 F-100!]

[link:www.westlakevfd.org|Westlake VFD Website]