gnarlynick2072
New member
Have a 98 3.4 with a 5 speed. The truck has been great but lately through the 2-2500 rpm range I get a harmonic exhaust noise. Sort of sounds like those old Suburbans that go "wong wong wong wong wong" which increases in rate through the RPM band. ALSO this only happens when it is hot outside, it goes away when the air is colder. My first guess is that this is an exhaust valve out of adjustment (or 2 or 3...)
This came at about the same time I started getting idle problems. I get a shake at the normal idle speed but it hovers strangely over 700 then slightly under 700. For those with 5 speeds it should idle RIGHT at 700. I changed IAC and cleaned MAF and checked vacuum leaks and sparkers. No codes. Fuel economy is still awesome (~22 mpg highway, lifted, arb bumper, winch)
To give some background I had one incident where the engine took some water but didn't stall out. The engine returned to normal faster than I could stop to blow any potential water out the sparker holes. I had a valve tick for about 30 seconds which then went away. After that I did the basics, changed oil, fluids ect...
Compression test came back:
1: 120/135
2: 130/135
3: 130/140
4: 145/150
5: 135/135
6: 132/135
In the back of my head I think it's a ticking time bomb, but the valves I believe are the culprits and the last stand to finding out if it really will be toast in a few years.
Any thoughts?
This came at about the same time I started getting idle problems. I get a shake at the normal idle speed but it hovers strangely over 700 then slightly under 700. For those with 5 speeds it should idle RIGHT at 700. I changed IAC and cleaned MAF and checked vacuum leaks and sparkers. No codes. Fuel economy is still awesome (~22 mpg highway, lifted, arb bumper, winch)
To give some background I had one incident where the engine took some water but didn't stall out. The engine returned to normal faster than I could stop to blow any potential water out the sparker holes. I had a valve tick for about 30 seconds which then went away. After that I did the basics, changed oil, fluids ect...
Compression test came back:
1: 120/135
2: 130/135
3: 130/140
4: 145/150
5: 135/135
6: 132/135
In the back of my head I think it's a ticking time bomb, but the valves I believe are the culprits and the last stand to finding out if it really will be toast in a few years.
Any thoughts?
