My 87 d150 slant has a engine miss. I have changed the spark plugs, plug wires, distributer cap, rotor button, pcv valve, breather, fuel filter, air filter, air cleaner mounting gasket. Checked timming- good. Vacuum seems good - no leakes. STILL HAVE A MISS.

I think I know were to go next. The carb leaks alittle gas down the side, thinking a rebuild would be a good place to start?
Could cloged cats cause a miss?

Any help guiding me in the right direction would be great!!!
I am about to pull out my hair and I am bald lol

Step 1: do a full engine compression test (dry & "wet"). Nothing you did will help if you have a mechanical fault with your engine. Post results & we can go from there.

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63 Valiant Wagon
225 - 4 bbl

Agree with wagons on this one. The compression check will tell you whether it is IN the motor or attached to the motor. Seems like I may have to take a weekend when I get home to come turn wrenches for fun. Im sure if its not sorted by the time I get there. And since you have a truck (no cupholders) check out mine in the slixer gallery "oldy but goody" you may like it.

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225, Offenhauser, Holley 350, A833OD, 3:55, GM HEI,99 Durango starter
BOOSTED! WH1C, BIG FMIC, 10#
Operation Noble Eagle 03-05
Operation Iraqi Freedom 05-07
Operation Enduring Freedom 12- 13

are you SURE there is no vacuum leak?

my 83 D-150 had a miss at idle,
when I checked the timing, I could see that the timing indicator, when froze under the strobe, was shifting constantly..

removed the lean burn and initially went to a points distributor then a HEI,,
with both the miss went away and the timing mark was rock solid.

Love the truck ssg

Ok guys. Did the compression check, it checked ok.
Took the truck out for a drive today. Shakes bad unless you are on the gas. When you get ready to stop and take your foot off the gas and push in the clutch it dies, every time.
When you get into the gas hard and get the rpm's up the miss seems to go away.

Leads me to belive its eather carb or vacuum.
I checked the vacuum and its seemed good, maybe I missed something.

Any help would be great

When you get into the gas hard and get the rpm's up the miss seems to go away.

I had the same until I went full GM HEI with new cap rotor etc. When I first switched to HEI it would still kind of miss but that was to a white crudy build up in the cap and rotor area. I swapped the whole dizzy for a non lean burn one and went w the site recommended rotor etc. Like a singer sewing machine now. Just work one thing at a time and it gets better as you go. Id say for vacuum leaks, check it when its cold by shooting the seams of the intake etc and carb mount with starting fluid. If it gains rpm then theres a leak. A vacuum guage would also clue you in as well if there is other issues.

Thanks for the compliments, its far from done.

let us know what you find.
Pohlman

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225, Offenhauser, Holley 350, A833OD, 3:55, GM HEI,99 Durango starter
BOOSTED! WH1C, BIG FMIC, 10#
Operation Noble Eagle 03-05
Operation Iraqi Freedom 05-07
Operation Enduring Freedom 12- 13