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Background. Engine replaced and has about 15k miles on it. Ran awesome for a few years and then I started noticing some lower power at load and high throttle. Missing and sounds like misfires in engine. It got worse and worse to the point of not being able to go up a simple hill.
No vacuum leaks. Even the elbow behind engine. Fuel pressure checks out. Changed all injectors. COPs are fairly new. Replaced fuel filter AND fuel sender module in tank. Air filter replaced. MAF unplugged results in same issue.
Removed entire exhaust system to eliminate clogged cat and o2 sensors as the DTCs did note o2 sensor issues but I have read many things can cause this.
After all this with exhaust removed it idles fine but SAME issue with revving it up. Once past half throttle and smashing peddle in park it sputters and just misses like it has a plug issue or fuel issue.
Yes brand new factory engine. I haven’t checked the other items you mentioned. I can check fuel pressure again at wot but don’t know how to see if skipped timing.
Yes brand new factory engine. I haven’t checked the other items you mentioned. I can check fuel pressure again at wot but don’t know how to see if skipped timing.
Ok have made some progress. Grabbed a fuel pressure tester and hooked to schrader valve. No pressure. Maybe a pound. I looked underneath and remember when I last changed the fuel filter I broke a quick connect tab to the filter. I chopped the lines and used barb fittings. Well one of the patch jobs I did was kinked. Fixed the kink with new fitting and pressure was now 30 while running. Revved slowly up to 5k and pressure never dropped. Pulled off regulator vacuum hose and it jumped to 40psi.
I am closer but still noticing something strange. The entire exhaust is off the vehicle except the manifolds. I do have a small leak in passengers side manifold but when I SMASH the pedal the pressure actually increases a bit but the engine stumbles pretty bad.
if you slowly increase throttle up to high rpms very smooth engine. But smash it and very bad stumbling. Any ideas on this one? Would the exhaust being removed with no O2 sensors cause this behavior ?
if you slowly increase throttle up to high rpms very smooth engine. But smash it and very bad stumbling.
Would the exhaust being removed with no O2 sensors cause this behavior?
The upstream O2 sensors help to regulate the air/fuel mixture, so I would go with a "yes" on that.
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