# 1985 Ford F150 engine misses **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ford\ **Created:** [July 26, 2012, 9:01pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773 "2012-07-26T21:01:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![holersl](https://avatars.discourse-cdn.com/v4/letter/h/85f322/32.png) [@holersl](https://community.cartalk.com/u/holersl)\ **Post date:** [July 26, 2012, 9:01pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/1 "2012-07-26T21:01:36Z")
I am stumped. I’ve had my mechanic work on this issue (the engine misses), and for the past few months thought the issue was resolved… Truck is 27 years old and has only 75K actual miles. Here’s what I have done. Installed rebuilt carburetor - 2009 New plugs, wires, distributor cap and rotor - 2010 Adjusted carburetor, timing, and choke - Feb 2012 I normally drive it every couple days, yet during last winter it set up for a couple weeks with 10% ethanol fuel. In early spring, the engine started missing while driving (about 1/3 of the time). After taking to the shop a couple times, my mechanic basically gave up. I believe it’s time for a new mechanic. I may also give up and just get a newer truck, but not quite ready yet. I suspected water in the tank, knowing that ethanol can attract moisture, so i ran the tank dry then bought 5 gallons ethanol free fuel (i live in the country where we can still find it). Engine started, ran great for a few months, and i thought i had solved the problem…until yesterday, when the engine started doing the same thing again just as it did when the problem originally started. I would like to have some thoughts before I take it to another mechanic, so please send them my way ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [July 26, 2012, 9:55pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/2 "2012-07-26T21:55:17Z")
Has anyone checked for a stretched timing chain? Tester ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 26, 2012, 10:11pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/3 "2012-07-26T22:11:34Z")
Is it the 6 cylinder or 8 cylinder engine? The Winsor V-8s are notorious for jumping time while the 6 has a gear and rarely skips. Both engines used a mixture control solenoid on the carburetor that could cause problems. When the engine is warmed up and idling partially close the choke and listen for the engine to either increase or decrease rpms. If it increases the carburetor is leaning out. If if stalls down the carb may not be the problem. ---
**Author:** ![kawasaga](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kawasaga](https://community.cartalk.com/u/kawasaga)\ **Post date:** [July 26, 2012, 11:07pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/4 "2012-07-26T23:07:39Z")
These engines do not have tioming chains…intake manifold or EGR leaks were very common…check that. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 26, 2012, 11:30pm UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/5 "2012-07-26T23:30:37Z")
@kawasaga - the v8s sure do: ![](http://i.ebayimg.com/t/Ford-302-351W-Early-Double-Roller-Timing-Chain-78120-/00/%24(KGrHqV,!k8E3HurhsV7BODJg,foew~~0_35.JPG) ![](http://www.autoguide.net/apf//images/agfor302lb.jpg) ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [July 27, 2012, 12:09am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/6 "2012-07-27T00:09:30Z")
With a poeblem that comes & goes as yours does I’d not be inclined to look at cam timing first, since once a chain wears it stays worn and if it slips it stays slipped. Have you checked your fuel line pressure? This sounds to me like a fuel problem, either metering, pump, filter, or line. If this is a 27 year old pump…well…perhaps… ---
**Author:** ![kawasaga](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kawasaga](https://community.cartalk.com/u/kawasaga)\ **Post date:** [July 27, 2012, 12:26am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/7 "2012-07-27T00:26:44Z")
I was talking about the 6 cyl really…sorry. ---
**Author:** ![kawasaga](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kawasaga](https://community.cartalk.com/u/kawasaga)\ **Post date:** [July 27, 2012, 12:38am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/8 "2012-07-27T00:38:31Z")
Ohh…the V-8 carbs never had closed loop control…only the 300-6 did…except for a few in Conada.,…never did the V-8 trucks have O2 feedback. ---
**Author:** ![holersl](https://avatars.discourse-cdn.com/v4/letter/h/85f322/32.png) [@holersl](https://community.cartalk.com/u/holersl)\ **Post date:** [July 27, 2012, 12:40am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/9 "2012-07-27T00:40:39Z")
It is straight line 6 ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [July 27, 2012, 12:42am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/10 "2012-07-27T00:42:42Z")
Excellent. Lots of room under the hood to sork in. Let us know how that fuel pressure test works out. ---
**Author:** ![holersl](https://avatars.discourse-cdn.com/v4/letter/h/85f322/32.png) [@holersl](https://community.cartalk.com/u/holersl)\ **Post date:** [July 27, 2012, 12:51am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/11 "2012-07-27T00:51:01Z")
holersl writes to say it is a straight line 6 cyl. 300 [cu.in](http://cu.in). Pretty standard. ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 27, 2012, 12:56am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/12 "2012-07-27T00:56:51Z")
Is the problem a real dead miss on one cylinder that can be isolated, or is the engine running rough at idle? ---
**Author:** ![holersl](https://avatars.discourse-cdn.com/v4/letter/h/85f322/32.png) [@holersl](https://community.cartalk.com/u/holersl)\ **Post date:** [July 27, 2012, 2:40am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/13 "2012-07-27T02:40:31Z")
The engine runs rough on the road and also at idle. The miss is not in sinc with any cylinder misfiring but is intermittent. ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 27, 2012, 2:49am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/14 "2012-07-27T02:49:59Z")
Grab the top of the carburetor and try to twist it. The throttle plate screws may have worked loose. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [July 27, 2012, 2:50am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/15 "2012-07-27T02:50:49Z")
- Coil. Have the shop put it on their ignition analyzer. Verify correct spark amplitude. - Gummed up fuel system. Drain tank, flush w/fresh gasoline, change fuel filter, maybe try some carb cleaner. - Vacuum leak. Have the shop test all vacuum hoses and each vacuum operated device for diaphram leaks. - Stuck valve, non-sealing ring, bad head gasket, etc. Have the shop do a compression or leak-down test. - Carb problem. Ask the shop to put another carb on it, borrow it from another truck if necessary, then drive it for a week as a test to see if the problem goes away. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [July 27, 2012, 2:51am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/16 "2012-07-27T02:51:26Z")
Remove the distributor cap. Put a socket with a breaker bar on the crankshaft bolt. While someone watches the rotor in the distributor and rotate the engine in one direction and stop. Now rotate the engine in opposite direction. If the engine can be rotated in the opposite direction more than 5 degrees before the rotor in the distributer begins to rotate the timing chain is stretched. Tester ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [July 27, 2012, 2:57am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/17 "2012-07-27T02:57:07Z")
I just don’t see this as a likely timing chain problem. It could be that of course, and the symptoms are somewhat consistent with a timing chain problem. But the truck only has 75K on it. Wouldn’t it be unusual for a timing chain to go bad at such low mileage? ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 27, 2012, 3:06am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/18 "2012-07-27T03:06:39Z")
The 6 cylinder has timing gears… No chain. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [July 27, 2012, 3:48am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/19 "2012-07-27T03:48:37Z")
You guys are right. The 300 CID had timing gears not a chain. However, if this engine has the original timing gear set the cam gear has plastic teeth. These plastic teeth have been known to shred off the cam gear throwing the ignition and valve timing off. So you can use the rock the engine back and forth method to see if the gear is worn. One of the other ways to determine if the gear is shredding it’s teeth is to drain the oil. And if small bits of plastic are found in the drained oil the cam gear is shredding it’s plastic teeth. Tester ---
**Author:** ![kawasaga](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kawasaga](https://community.cartalk.com/u/kawasaga)\ **Post date:** [July 27, 2012, 11:50am UTC](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773/20 "2012-07-27T11:50:36Z")
The 300-6 NEVER has head gasket trouble. It does, however have a PITA two -iece intake / exhuast that tend to leak (vacuum and exhaust)… If you put gaskets on the exhaust, it will not last long so I’d beware of that…Spray carb clean around the EGR and intake and I thnk yu’ll find a bit of RPM rise. 🙂 [Next page](https://community.cartalk.com/t/1985-ford-f150-engine-misses/73773.md?page=2)