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Help tracing down vacuum leak on 4.0 ohv


DBS

New Member
Joined
Apr 20, 2015
Messages
1
Vehicle Year
2000
Transmission
Manual
I have 2000 ranger with a 4.0 ohv that I just replaced both heads due to cracks. Owned 2 years and condition was pre-existing. Was throwing 171 and 174 codes since last year, but otherwise ran ok, with the exception of an occasional misfire. Used oem head and intake gaskets during reassembly. Started right up but runs extremely rough. During idle misfires every few seconds and the engine "jumps" a little. During a couple of short test rides, I can hear sputtering and popping. All vacuum lines have been checked and cannot find anything obvious. Hooked up my scanner and recorded live data and transferred to excel to create a graph, which is attached. The bank 1 short term fuel trims look ok but the bank 2 are way too high and more erratic. Long term trims are both high and have a large difference between them.

Someone on another forum suggests intake gaskets may be the culprit, which I considered was my worst case scenario. I'm trying to eliminate any other causes before I go down that road. Based on what I mentioned above and the graph, does anyone see anything I should focus in on? Thanks.
 

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