Rough idle...

[69-]

No need to double check with two gauges. So very slight movement of 1/8th of an inHg is quite acceptable.

Now, back to the slightly low reading. Vac lines?
I'd expect something in the range 17-19 for a healthy engine steady at idle.

Quickly opening and closing the throttle lets the reading drop to 0-5 inHg and then go up high above 20 to then (slowly) return to your idle reading?

 

[53ryder]

Waited to see what vacuum test showed before getting after vacuum lines. Now the next thing to do.


One question for now. The thin vacuum lines (roughly 1/8 inch thick or 4mm), like the one that attaches to the EGR valve, on my engine seem to be very stiff and harder that the larger lines running around. Do these thin lines have a different name for them? I guess when I think of vacuum hoses I think of the thicker, softer hoses that are around 5/16th to 9/16th in thickness.

 

[Ele115]

I've got a 76 Cordoba with a 400 and it sits a lot. I just replaced the vac lines, T's and fittings for under $15. They all looked like they day the car was built but most of them were swollen badly at the metal bung and some split when I grabbed them. $15. I also found a spring on the carb that's a tad weak so I found a better one. If you have any doubts, a can of good carb cleaner or propane can help you find a leak too. And it's not just the lines. It could be a gasket.

Vaccum gauge Borrow one or buy for $20
Vacuum lines $10-15
Carb cleaner $4-5

Total $34-$40

Shop charges: $ 120-$200

 

[UNKIE]

I've replaced the car's spark plug wires rotor and cap plugs and an Ignition Module Control Unit. The dang thing still runs roughly today I checked the tune and the vacuum is still between 15 - 18. So I thought what the hell it. I'll replace the brake hoses and calipers up front and the only line wrench I don't have is the one needed for that hose. I'll run a compression test and get out my leak-down detector. The way my luck has been lately I'll need a new power pack. the fella that had it before me took the lean-burn off then messed with the aspirator tube and welded it shut but it still has an exhaust leak.

​

 

[UNKIE]

Waited to see what vacuum test showed before getting after vacuum lines. Now the next thing to do.


One question for now. The thin vacuum lines (roughly 1/8 inch thick or 4mm), like the one that attaches to the EGR valve, on my engine seem to be very stiff and harder that the larger lines running around. Do these thin lines have a different name for them? I guess when I think of vacuum hoses I think of the thicker, softer hoses that are around 5/16th to 9/16th in thickness.

I got this on the Amozn like $9 bucks for 10 ft. I got the red they have black as welll and all sizes as well. I hope I didn't just get in dutch with anyone.
KDP Silicone Vacuum Hose Line, ID:1/8"(3MM) OD: 0.35"(9MM) Wall: 1/8"(3mm) 10 Feet Per Roll (3M) Red 60 ps Air or Water Transportation

 

[ffaruqi]

UNKIE, can you confirm that the "KDP Silicone Vacuum Hose Line, ID:1/8"(3MM) OD: 0.35"(9MM) Wall: 1/8"(3mm) 10 Feet Per Roll (3M)" is the correct size for a '87 Fifth Avenue? I was going to buy some soon. Thanks for posting that info!

Fred

 

[Master M]

One question on plugs. Have done them before several times on other cars. Ordered these Bosch plugs from Rock Auto. A different kind of tip, supposedly fits my 5th Avenue. Okay to use or get some more 'traditional' tipped plugs? I dunno!View attachment 44534 I've just never used this kind of tipped spark plug before. How about you all?

I use the Bosch Platinum +2 in my 1988 5th avenue with all of the original factory Lean Burn equipment and they work excellent, idle to highway speeds.

 

[53ryder]

I ended up using. Champions