Rough Idle

[JohnnyC5]

maybe a stupid question but if a intake manifold gasket is leaking will it cause a rough idle? If so what should all be replace when removing a intake manifold. simple parts that could have gone bad that should be replaced when thats off.....any help would be nice. i know that i will need a car gasket and the manifold gasket. would it be worth replaceing the fuel pump while its off. it only has 88000 miles on it.

[Uneek98]

It sure can. With it running spray some carb cleaner around it and idle will change if the gasket is bad. I say for fuel pump if it ain't broke don't fix it.

[Uneek98]

Ok just saw your other post. Just replace the gaskets and that's it in my opinion.

[JohnnyC5]

cool will do

[recian]

Grab a few feet of vacuum hose since these trucks stopped in 96. I have yet to see a car made from 96 back that doesnt need vacuum hoses just from age and heat. Not to mention they usually break when you take em off. Sometimes you'll have to cut em off.

[JohnnyC5]

Well I am wondering if the intake manifold is cracked. I was just going to unbolt the min I needed to get the new gasket on but i am thinking of replacing the carb gasket and head gasket while Iam at it. (and now the hoses) I put some gasket maker on the top seal along the intake manifold where the leak was thought to be but it has not affected it at all. I will make a video and post it to youtube tomorrow of whats going on. I pulled the pcv valve and realize how important the vacume lines are, I think I will start looking at the webber carb to get rid of them. I just want a realible daily driver nothing stupid powerful. I think I will put the eletrical fuel pump on as well. How much am I looking to spend between the webber carb and a eletrical fuel pump, just a ball park????

[camoit]

3 bills easy. You might get it a Little cheaper if you search around. Some of the guys on here know where to find them at a decent price. We have a sticky in the performance section on the weber. Look in there first. If I was you I would pull the manifold with the carb on it and see just how deep you need to go. If you need a manifold there pretty common.

[DroppedMitsu]

It wont pass visual smog check if you install a weber, gotta keep the oem carb, damn Cali.

[JohnnyC5]

I am going to register it in tx. All I have to do is pass smog for a base sticker. What's visual smog???

[DroppedMitsu]

When they smog your vehicle they check everyhing over under the hood to make sure its all there and not tampered with/modified.

[JohnnyC5]

ok i have found out ill never have to visually smog the car. texan does not require a inspection on classic vehicals. ill pay for classic plates befor i move back to texas. california all i need to do is pass emissions to get a base sticker. so i really am not worried about visual smog. does any one have a ling to the webber carb install i cant seem to find it. i have found a lot of talk about it but noting about the actual install and what hoses to get rid of. Ill be instaiing a fuel pump when i get the webber carb.

[camoit]

look in the manuals section> first gen factory manual> weber carb.

[JohnnyC5]

http://www.webercarbsdirect.com/product_p/wk614.htm

this is what i am looking at..
maybe i am dumb but i cant find the exact weber install in the forum. a link would be nice.

[camoit]

I thought you had a Webber and was looking for a manual.

Try looking at this thread to find out about the best fit.
http://www.mightyram50.net/vbulletin/showthread.php/210-Weber-32-36

[manorchurch]

maybe a stupid question but if a intake manifold gasket is leaking will it cause a rough idle? If so what should all be replace when removing a intake manifold. simple parts that could have gone bad that should be replaced when thats off.....any help would be nice. i know that i will need a car gasket and the manifold gasket. would it be worth replaceing the fuel pump while its off. it only has 88000 miles on it.

Throttle pivot sleeve bearing = rough idle. Spray vacuum pump oil on the manifold gasket seams -- not carb cleaner. It stops up leaks for a few minutes and smoothes the idle before the oil gets sucked in and burned. Rough idle, imho, is rarely a vacuum leak in the manifold and carb mount. Whoever mentioned refreshing the vacuum lines is right -- but sometimes it's one bad plug wire. Little bit of arc-over through the cable insulation, little bit of miss. You can usually see the spot at night when lights are out.

[JohnnyC5]

= rough idle. Spray vacuum pump oil on the manifold gasket seams -- not carb cleaner. It stops up leaks for a few minutes and smoothes the idle before the oil gets sucked in and burned. Rough idle, imho, is rarely a vacuum leak in the manifold and carb mount. Whoever mentioned refreshing the vacuum lines is right -- but sometimes it's one bad plug wire. Little bit of arc-over through the cable insulation, little bit of miss. You can usually see the spot at night when lights are out.


I just did plugs and plug wires you think i might take em out and check em. is it possible to have bad wires out of the box. ill look for the vacume pump oil at auto zone and give it a shot. Throttle pivot sleeve bearing, where is that located and how do i check it. I am 100 percent sure on changing the carb i think camoit is going to come down and give me a hand (if i am lucky ) when i do it, get rid of the vacume line and remove that problem from the situation.

[camoit]

Clean out the EGR valve. Take it off and clean out the carbon. It will cause a rough idle.

[manorchurch]

I just did plugs and plug wires you think i might take em out and check em. is it possible to have bad wires out of the box. ill look for the vacume pump oil at auto zone and give it a shot. Throttle pivot sleeve bearing, where is that located and how do i check it. I am 100 percent sure on changing the carb i think camoit is going to come down and give me a hand (if i am lucky ) when i do it, get rid of the vacume line and remove that problem from the situation.

Okay, it's probably not the wires. I had one once that would idle perfectly, then start to miss at about 2800RPM. Drove me crazy tracing through fuel delivery system, and finally found the #3 plug wire was breaking down internally at higher RPM. Camoit is right about the EGR ... something I don't think of because I spritz the EGR when I change oil.

The carb throttle plate pivots inside a sleeve bearing that's part of how it mounts inside the carb throat. An old carb can have some degree of wear in that bearing, and a little bit of outside air gets piped in, causing a little "boop" as the idle circuit unbalances every few seconds. It's annoying, but harmless - the sort of thing that finally convinces you to buy the Weber. Or go MFI :-)

I have heard that old-age failures in the jet valve assemblies can cause enough in-the-cylinder mixture irregularities to make a miss. Solution: non-MCA head. Don't go for that "put a bolt in the jet-valve hole" treatment. I still think it makes hot spots that are worse than the disease.

[camoit]

Well he drove the truck by Area 51 today. It idles pretty rough. The T stat is stuck open so it never gets hot. The fan clutch is frozen. It runs ice cold. I never did a lot of work with the feed back carbs. He is going to replace the t stat and replace the clutch. He is also going to replace the O2 sensor and fuel filter. I'm thinking the carb is stuck in a cold loop. But as for the rough idle once we get the thing to get hot. It might fix part of the problem. Next I suggest we look in at the jet valves and an elimination kit, carb and header. Any other ideas?

[JohnnyC5]

camoit has the best area 51 i have ever seen..... I have cleaned the egr valve it was sticky and drity. still running rough but not as bad.

[JohnnyC5]

No T stat at all. I flushed out the radiator and refilled it put on the new cap, installed a Tstat. Have not had the time to drive it yet but it runs a little smother and the heater working is nice.

[manorchurch]

Well he drove the truck by Area 51 today. It idles pretty rough. The T stat is stuck open so it never gets hot. The fan clutch is frozen. It runs ice cold. I never did a lot of work with the feed back carbs. He is going to replace the t stat and replace the clutch. He is also going to replace the O2 sensor and fuel filter. I'm thinking the carb is stuck in a cold loop. But as for the rough idle once we get the thing to get hot. It might fix part of the problem. Next I suggest we look in at the jet valves and an elimination kit, carb and header. Any other ideas?


I think you're right, the carb is in cold mode. Main thing being that you can't diagnose anything else until there's a working thermostat.

[pennyman1]

check the vacuum hoses, especially the ones in the box on the left inner fender - it controls the carb for rich/ lean but the bad hoses also cause rough idle and poor power.

[JohnnyC5]

I think me and Camoit are going to drink some beers and replace the old carb in a week or 2. Looking for a fuel pump and regulator now.

[JohnnyC5]

How much better is the gas milage with that header. does the webber carb and eletric fuel pump make the gas miliage go up as well?

[JohnnyC5]

oil filter, fuel filter, air filter, oil, front shocks, fan clutch, replaced the leaking oil pressure line on the block, thermostat, egr valve cleaned, plugs, wires, rotor cap, distributor cap, radiator flushed, replaced the radiator cap, idler arm. Still rough idle(I know some of thoes things wont help the idle but i wanted to brag) what eles can i check before I do the carb????

[JohnnyC5]

oil filter, fuel filter, air filter, oil, front shocks, fan clutch, replaced the leaking oil pressure line on the block, thermostat, egr valve cleaned, plugs, wires, rotor cap, distributor cap, radiator flushed, replaced the radiator cap, idler arm. Still rough idle(I know some of thoes things wont help the idle but i wanted to brag) what eles can i check before I do the carb????