Vaccum guage connection

[frogman112]

I have a 2004 4-Tec GTX normally aspirated and would like to connect a vacuum gauge to perform some diagnostics. I couldn't find any other than ones before the throttle body. Any suggestions for a connection point after the throttle body to monitor intake manifold conditions?

 

[ski-d00]

There are none unless you remove the existing sensors but that will cause issues or you can make your own ports but kind of pointless really. If you want to perform diagnostics, you will need BUDS or CanDoo which will tell you everything like MAPS, MATS, etc. and be able to test sensors as well.

Do you have a problem? If so, just tell us what it is doing and I'm sure we can help out. Do you have any codes? Have you pressed set 5 times to check while the issue is happening?

 

[beerdart]

There are three nipples on the intake manifold just below the injectors you just need to drill them out a hot nail works great.

 

[frogman112]

The RPM fluctuates ~200 - 400 RPM at idle (on trailer and in the water) as well as anywhere below 5000 RPM. At 5000 RPM it stays steady. It lacks power on acceleration until up to 5000 RPM. There are no codes. I did not hit set 5 times while it was happening.

These are the things I tried last season with no change;

New plugs.
Primary and secondary coil resistance was good.
Fuel pump has only 30 hours on it but I hooked up a fuel gauge in-line. It was 43-44 psi and held steady even after shutting off for 10 minutes.
Pulled injectors / rail. No leakage after 10 minutes.
Installed a used (good) cam position sensor but no change.
Installed a new TPS. Pulled IAC valve, it was very clean. Checked resistance of both circuits. Spec is 50 ohms @ 70F. Both of mine were 73 ohms @ 66F. Had them both recalibrated on BUDS but no change.
Pulled the MAPS and it was very clean. I was going to back prob to check voltage at various vacuum levels but have not done so yet.
I was hoping to have a vacuum port to perform a smoke test and monitor fluctuation. Thanks Beerdart, I may try opening up one of the nipples below the injectors.

 

[frogman112]

Forgot to update this post when I solved the problem. It ended up being a bad coil.