86.5 Nissan hardbody 2.4FI sputtering under acceleration, worse when engines cold, clears at 3 grand.air filter soaked

[66buickguy]

Hey guys and gals.....I have an 86.5 Nissan hardbody 2 wheel drive 2.4 liter FI 4 cylinder 5 speed extended cab and just kind of looking for some suggestions........the truck has started sputtering really bad under acceleration and worse when engine is cold.......the more I push on the gas the worse it gets until I let up unless I let it chug for 10 seconds then it will come out of it at roughly 3,000 rpms and run fine........also sometimes it will miss at idle even when engine is at running temp........ this problem occurs occasionally when the engine is at running temperature but definitely more pronounced when cold...almost like something is choking the motor.........the truck has had a problem for a few yrs where I have to push on the gas to get the engine started after its warmed up then it pukes out a bunch of black smoke and used to run fine.......air filter also just started to get soaked with engine oil in about 2 months...........I've pulled the passenger seat to check codes and my computer has no switch to do code search....it has the green light but no code search knob or switch.......plug wires, distributor cap, plugs, rotor, fuel pump, fuel filter....all new within the past 6 months......I'm at a lose.... any suggestions appreciated

[sx moneypit]

Moved this to the correct forum.

[Adverse Effects]

have you done a compresion test on it?

all of that sounds like low compresion

[66buickguy]

I haven't done a compression test yet.....might try to do that today......what should the range be?.....she does have 330,000 miles on stock pistons and rings......it's just so weird how it's kind of an intermittent problem after the engine gets to operating temp.....sometimes at operating temp it runs fine then other times I can watch the shifter jump back and forth like the engine is firing on only 2 cylinders while idling.....sometimes giving it a good Rev will stop the miss ..other times no dice....just within the past few months it started doing the sputtering thing when engines cold and also started soaking the air filter with oil .....it happened so quick I'm wondering if maybe some vacuum controlled object or electrical engine component possibly went bad......

Thanks
Mike

[Adverse Effects]

it dose sound like the rings (at lest) are shot and its causing lots of blow by and that is what is putting oil in to the air cleaner

it also mokes the motor struggle at low REV's to suck enough air in to burn that is why under 3K RPM it plays up like a $2 whor

[nalz]

Might also check your PCV valve, it should allow airflow in one direction, then block it in the oposite direction. Is oil level at proper level (any chance it's overfilled?)

[66buickguy]

Engine oil is slightly under the full mark.....it does use about a quart every month or so......ran a compression test.....all cylinders were between 130-145 PSI.......I did notice the EGR valve is rattling like a paint can but quiets up when I slightly press on the diaphragm. ...then the engine idles down so it seems to be working.....this has me soooooo confused now......I was actually hoping to find a dead cylinder just to put my mind at ease.......PCV valve is also clean and working properly. ....only allows air to be sucked into the manifold ......kind of interesting getting that valve threaded back into the intake.... (tight space)......any other suggestions?

Thanks
Mike

[66buickguy]

Engine oil is slightly under the full mark.....it does use about a quart every month or so......ran a compression test.....all cylinders were between 130-145 PSI.......I did notice the EGR valve is rattling like a paint can but quiets up when I slightly press on the diaphragm. ...then the engine idles down so it seems to be working.....this has me soooooo confused now......I was actually hoping to find a dead cylinder just to put my mind at ease.......PCV valve is also clean and working properly. ....only allows air to be sucked into the manifold ......kind of interesting getting that valve threaded back into the intake.... (tight space)......any other suggestions?

Thanks
Mike

[66buickguy]

UPDATE!!!!! Truck now sputters worse while in the process of warming up when driving, doesn't do it so much if the engine is cold cold but about half way to running temp it falls totally on its face if the pedal is pushed to the floor.....It can still be driven if I nurse the gas but wont make it up any big hills......Even when engine is at full operating temp it still has this problem just not as bad......as soon as i shift into the next gear it will usually fall on its face then come right out of it.....Could this be a bad crank angle sensor in the distributor?

Thanks
Mike

[Adverse Effects]

is it throwing any codes?

[66buickguy]

My computer under the passenger seat has the green light on it but doesn't have a knob or any way to switch the computer to code check mode......I've taken the case off and checked the inside 3 times just to make sure I wasn't missing it and it's no where to be found.......not sure if it's possibly a late 85 FI motor computer or just an early yr 86.5.......did the 86.5's have the computer able to check codes?.....my Hanes and Chilton manuals both say to turn the screw/knob to code check mode but mine must have a pre yr computer or something. .....

Thanks
Mike

[Adverse Effects]

[66buickguy]

I ran a code search on the truck and nothing but the typical 23 and 24 codes that go away when the gear shifter is moved around and accelerator is pressed.......BTW my computer doesn't have the 5 different modes or the straight blade screw knob to do code search.....it just has a very tiny toggle switch on the back side of the computer to turn it either on or off for a very generic code search....... it does have a red and green light though........ I have since taken probably 20 ground wires loose all over the truck, cleaned them up with a wire brush and tightened them back up...... pulled the whole throttle body assembly off and cleaned everything I could...... replaced 80% of the vacuum lines even though the ones on there looked fine......... the fuel injectors seem to be spraying perfect..... I'm at a loss guys..... If I don't figure out something soon she's getting put on Craigslist for a really cheap price or going to the local scrap yard because I can't continue driving it like this... Anyone ever experienced this problem?....... it's been a damn good truck for many many many miles and many many many years but I think she might be finished........

Thanks

Mike