[PHXDMAX]

Cleaned the MAF this past weekend but still have the rough idle and SES light. Looks like I'll be doing a rebuild unless someone has any other suggestions.

 

[PHXDMAX]

I don't know if they have a flow match machine. The dealer is in Albuquerque and I brought it back to Phoenix. The injector was replaced at 197K. I guess I could swap injectors, clear the code and see what happens Don't know of it's using oil. No mention of it in the service records and I haven't driven it enough to know. I can't pass emissions at this point.

I did notice a knock/clicking noise when accelerating this weekend after cleaning MAF. Couldn't isolate it though. Maybe an exhaust leak?

Forgot to mention, no synthetic oil but my Dad was meticulous with maintenance.

 

[PHXDMAX]

I cleaned the MAF and no change. I swapped injectors, cleared the code and I'm now getting a generic P0300 misfire code. I went ahead an changed the intake manifold gasket, cleared the code and drove around the block a couple times and no code. Still idling a little rough though. Drove again a few days later and the P0300 is back.

Tuner Boost is leaning toward injectors so maybe I'll try some injector cleaner.

 

[PHXDMAX]

Well I pulled the injectors and made a test jig to clean them out. Measured resistance on them all first and they are all right at 13.1 ohms. Connected a hose to one, put some Sea Foam in the hose, applied about 20lbs of pressure behind the Sea Foam and pulsed the injector. It fired and shot out the Sea Foam. It was a steady stream like out of a squirt gun not a fan type spray like I expected. That may be because the pressure is too low. Anyone know what the fuel rail pressure is on this engine? 8th digit of VIN is a 'T'.

 

[PHXDMAX]

Thanks for the information. I have a scan tool that provides some live data but I don't see anything for misfire. I moved the injector a while back from number 2 to number 6 and the code changed to a random misfire P0300 code.

I raised the pressure last night and cleaned all injectors. 3 out of 7 were somewhat clogged. By that I mean they were not spraying a fan spray pattern but cleared after a couple of pulses. I have one that is clogged on one side and has a half fan spray pattern. It was getting late so I'll see if I can unclog the last one tonight. If I can't, I get another injector. Hopefully this fixes the problem and it's not valve train or bottom end.

 

[PHXDMAX]

Last injector cleaned up and had a good spray, Got it all back together and still have rough idle and P0300 code. Got a fuel pressure gauge and checked the pressure. Had 50lbs static and 49 running. As craigger325i said to should be 55-60. I pulled the vacuum line off the FPR and it wasn't leaking so I'll assume that it's good. I guess I'll try a fuel filter first to see if the pressure comes up and if not, I'll replace the fuel pump.

 

[PHXDMAX]

I can turn a wrench but I wouldn't necessarily say I know what I'm doing... Just doing a lot of research on this site. I pulled the intake manifold, cleaned everything up and installed a new gasket. I used the sea foam spray with the little hose that you pinch between the TB and intake tube and spray in while you rev the engine but didn't physically clean the TB. I haven't inspected the valves because the dealership did it a while ago. What specifically should I look for?

 

[PHXDMAX]

TB looked really clean but I went ahead and cleaned it anyway. No change. I guess I'll pull the intake manifold again and inspect it again.

 

[PHXDMAX]

Didn't have time this weekend to pull the intake manifold. Will do it later this week. I did however change out the fuel filter but it didn't help.

 

[PHXDMAX]

I let this project sit for a while as I just didn't have time to work on it. I finally got back on it last month and ended up taking it to a shop for a second opinion. The #2 cylinder was down to 50lbs compression. So I opted to get a used engine out of a 2004 Tahoe with 100k miles and all 8 cylinders reading 180lbs compression. While I was at it, I got a rebuilt tranny as the original was starting to slip. Dropped the engine and transmission in this past weekend and I'm in the process of hooking everything back up. Hope to have it running this weekend.