Javlin

I have a 1989 F-150 Lariat 92K with 5.0L 5 speed that is having a hard time accelerating up beyond 65mph ATTM.The motor off/on has a miss the last two months .I have put in thus far the EGR valve(code),Position sensor and what was really at fuult the EGR regulator.The motor has had plugs(E'S),wires,distributor,CTS,O2(code).Two spark plugs had alittle oil on them 4/8 put 8oz marvel to see if it might clean up the drain back holes abit.The other six plugs were a nice brown color.I have a new can for the tank swap(1yrold) new pump rail and supposedly two new in-tank pumps from the previous owner.I will say it ran better on tank two but not by much.
I have replaced the O2 back and forth with two new Bosch and the original I still have and got 41.The first time I got 96 I replaced the relay to which it came back on today.I am starting to suspect the rail pump(have spare) or fuel filter?Code 96 sounds like the pump is running to hard over energized ?The original O2 when I put it back in today was light grey while the Bosch was brown today coming out.The distributor last week made a big difference on the acceleration the valve clattered before is gone and was off by 5' at idle 15'BTC instead of 10' like now.Trying not to throw more money at the issue the Bosch O2 goes back in latter when she cools down.Thanks in advance for any ideas Kevin

Javlin

Read a nice little article here though for 92-94 my buddy the other day brought up the same option maybe ECM.It appears atleast for those years the ECM provided the ground for the heater on the O2.Google is your friend

http://askamechanic.info/askamech2/content/view/87/47/

Javlin

So last night she did not want to go above 2500rpm and took forever to get there.I got home I did a test while the engine was running no need to list them all about 4-5 coded main one 41 was still there.I went and got the fuel pressure tester KOEO got 25psi and it bled down before I had left work I had a new FF and replaced plugs 4/8 before that drive home.
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This morning ran the FG test again 25psi EO and 30psi while ER said FF first it was filthy install new one got 28psi EO and 32psi ER still flat though.So installed my backup line pump got about 30psi(?)EO and 34psi ER. I had read that some guys say that it runs better with the regulator unplugged did that got almost 40ps. but the gauge was bouncing reached to plug the vacuum line fuel was coming out of the regulator wa-la.I got the new regulator installed(PIN) have 34psi ER much better throttle response and was doing 4k rpm but has a stall at the bottom/miss and still getting code 41(lean) and 51(CTS) which I just replaced for GP.
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It still feels abit like timing or a dead injector somewhere.I think the code 96 for the FP relay over energized was a good indicator of a weak pump or running to much via the bad regulator.What's your guy's thought for the next move?I have an old O2 and going to run that test for the heater part but what else?

Javlin

Not a timing issue have left the fuel regulator unplugged since last post accelerates great but still getting the code 41.I just test the the heater on the O2 bought a 194 socket and a 921 bulb it works.I am going to order a NGK O2 see if it it is different and order a n adjustable fuel regulator the engine like 40psi and I may play a touch more.Also the CEL does not come on till about 15 minutes of driving and their is no change in drive-ability.The ECM does not supply ground(4wireO2s) only receives the signal still wonder about the ECM but then you would think the CEL be on at crank up.

Javlin

Well I think I found the problem a leaky capacitor

Javlin

Well got the computer installed today smoother idle/acceleration it took longer to happen but got code 41 took about 25 mins of driving and a 4000rpm run in 3rd gear.I did replace the vacuum line back to the regulator got 30psi idle 36/38 under acceleration.I am dropping in an NGK O2 Tuesday.I read somewhere here talk about the plenum gasket?Any thoughts out there?
I need to add that after I got the code I then went with the regulator unplugged 40psi and took it for another run CEL came on in 1mile.The second run occurred within 10mins of the first run so the O2 was really warm would that be a factor?

Javlin

I went back to the fuel rail pump again a few days ago kept thinking 30psi @idle and 36/38psi under acceleration but no load?it has to be dropping off even more than that while cruising.So I went and bought another inline Delfi Pump got 34/35psi @ idle and 38/40psi under acceleration.I reset the computer for 15mins. and installed an NTK O2.I read that these are often the OEM and it looked 90% the original to the holes on the O2 nozzle with slender design on the outward structure unlike the Bosch vane tip and stocky cylinder.I know it might not of made any difference but I was looking for a possible OEM performance/parameters.The battery was reconnected no CEL for over a 100miles yet before 45mph@2000rpm/4th gear now 48mph/2000rpm.I can now also take off easily in 2nd gear were it was a struggle the last six months.
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I am calling Case Closed!!