Unkonwn problem with motor
FTE Leadership Emeritus
Joined: Aug 2007
Posts: 42,085
Likes: 6
From: Lakewood, Ca.
True but people should learn something along the way. You can't just come here (or anywhere) and expect answers when something blatant is staring you in the face.
Try, just try and fix something yourself first and then ask for help. You'll never learn anything if someone always has the answers for you.
It seems like everyone these days just wants to take the easy way out. I don't know of anyone that could look at a broken fuel pump and not replace it immediately. Even if it doesn't fix the initial problem, at least you wouldn't have to worry about burning your truck to the ground.
Start from square one and take things one step at a time until you eliminate the problem. That's how you learn.
Try, just try and fix something yourself first and then ask for help. You'll never learn anything if someone always has the answers for you.
It seems like everyone these days just wants to take the easy way out. I don't know of anyone that could look at a broken fuel pump and not replace it immediately. Even if it doesn't fix the initial problem, at least you wouldn't have to worry about burning your truck to the ground.
Start from square one and take things one step at a time until you eliminate the problem. That's how you learn.
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
It's hard to follow his symptoms and he still didn't say if he had an automatic transmission or not.
I'd start there looking for vacuum leaks at or around the carb.
It could also be an issue with the distributor or timing chain causing the timing to jump around. He didn't say how many miles are on it either.
I'd start there looking for vacuum leaks at or around the carb.
It could also be an issue with the distributor or timing chain causing the timing to jump around. He didn't say how many miles are on it either.
Junior User
Joined: Jun 2007
Posts: 62
Likes: 0
From: Virginia Beach
Check for vacuum leaks
I'd use carb cleaner (I've heard propane works too, but I've never tried it) to check for leaks. If you hit a leak with the cleaner the RPM will change as it changes the air-fuel mix.
With the engine running(and cold) spray along the head/intake gasket, intake/carb gasket, and any vacuum ports off the manifold. Also check your hoses and the devices they're attached to for leaks.
Good luck, let us know what you find.
With the engine running(and cold) spray along the head/intake gasket, intake/carb gasket, and any vacuum ports off the manifold. Also check your hoses and the devices they're attached to for leaks.
Good luck, let us know what you find.
Elder User
Joined: Nov 2004
Posts: 666
Likes: 5
The Carter carb on the 300/4.9L is notorious for the screws that hold the base plate to the carb body coming loose. First, take off the air cleaner, then grab the body of the carb and try to wiggle it. If it moves, you will have to take the carb off of the manifold to tighten the screws. They go up from the bottom through the base plate into the carb body.
Mine has done this multiple times for the previous owner. When the body comes loose from the base plate, it screws up the mixture and causes a big air leak. The engine will rev, but makes little power. However, when this happens, it usually shows up even at idle and is not intermittent. But it could be that your's is just starting to get loose, and hitting a bump makes things worse for a moment.
The odd thing, though, is that you said that the engine revs, but the truck does not go any faster. If you have a manual transmission, there must be some mechanical problem, such as a bad clutch or some really weird problem with the clutch linkage. Neither one is likely to cause a problem that only shows up when you hit a bump. If you have an automatic, the sudden change in manifold vacuum could drive the modulator crazy.
Start with checking the carb body and see if it is loose. After that I don't have any more suggestions without more information. Do let us know what transmission you have, as that makes a big difference in pointing to possible causes/solutions.
Good luck,
Jim
Mine has done this multiple times for the previous owner. When the body comes loose from the base plate, it screws up the mixture and causes a big air leak. The engine will rev, but makes little power. However, when this happens, it usually shows up even at idle and is not intermittent. But it could be that your's is just starting to get loose, and hitting a bump makes things worse for a moment.
The odd thing, though, is that you said that the engine revs, but the truck does not go any faster. If you have a manual transmission, there must be some mechanical problem, such as a bad clutch or some really weird problem with the clutch linkage. Neither one is likely to cause a problem that only shows up when you hit a bump. If you have an automatic, the sudden change in manifold vacuum could drive the modulator crazy.
Start with checking the carb body and see if it is loose. After that I don't have any more suggestions without more information. Do let us know what transmission you have, as that makes a big difference in pointing to possible causes/solutions.
Good luck,
Jim
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