2002 ranger 3.0 aod engine? bucking

glindy · #1 03-27-2012, 10:14 PM

I just purchased a used 02 xcab 3.0 at as is and it has some issues. The truck has 2xx,xxx mi but the engine seems to run well,except when it exceeds 3500+ rpm, then either in OD,third,or dropped in 1st gear the engine seems to severely buck like its running out of fuel or cutting out. If you let off the gas it runs OK,I was thinking fuel pump,filter,coil pak,wires,plugs possibly,which I plan on doing overall GM on it anyway. Any ideas on other probable causes so I don't become a parts replacer?

Also it sounds like a jet under the hood as rpm's increase,I was thinking trans slipping,but rpm remains steady with speed of vehicle. Next I would think that it has a slipping fan clutch,or does it have an electronic fan control that would do this?

And of course I get to replace the front ball joints,which I could tell by tire wear were bad.

Appreciate any ideas
Thanks lindy

nicktheman2013 · #2 03-28-2012, 03:32 AM

I don't think in 2002 the 3.0 came with electronic fan unless it's aftermarket. But sounds like a fan clutch. As far as bucking probably in need of a tune up

glindy · #3 03-28-2012, 09:07 PM

Thanks,
I just stuck my head under the hood and started playin,the fan clutch was locked solid. Only 60 bucks,but getting it off was a bear,the tools they loaned me did nothing,as it has a recessed pully where the bolts sit and they were made for one where the bolts stick out. Luckily my trusty pipe wrench grabbed the back of it after moving AC line,but it still wouldn't budge with 3ft cheater. Made use of my air hammer and gave shaft a beating,then it broke loose.
Started tune up and already found vacuum leak at pvc rubber,changed oil,and started on plugs,fuel system. It does have a whine somewhere underneath,maybe fuel pump,TC? Too dark now to do anymore.

GLH · #4 03-29-2012, 01:16 AM

Be sure and use all Motorcraft parts or it will blow up ! (jk)

glindy · #5 03-30-2012, 06:11 PM

OK,
I did oil change and changed wires and new autolite plugs,it still runs bad and shows PO305 #5 misfire. swapped plugs,still missing.swapped wires still missing.
Installed new cam synchronizer,which looked like it was off a notch still missing. check 4,5,6compression ~130,should be firing but not.
Checked injectors,15 ohms,went ahead and replaced #5,still missing.

What next? Could it be 1,2,3 side and just showing #5?
What else would kill just one cyl? Don't have tools to check Inj electrical signal to see if theres a short.

nicktheman2013 · #6 03-30-2012, 09:40 PM

Reset the ECM take the negative battery post off for 10 minutes. Our engines are computer controlled and adapt to situations your truck may be still thinking there's a problem somewhere and needs to be reset. Happend when I got a new battery and cables the idle was a bit different it jumped around looked In my manual unplugged the negative for ten
Minutes it reset the ECM then let it run for about another 10 minutes idle to re adapt and it was good. Never realized that a new battery and cables would throw it off but heck figured it was worth a try

koolj3 · #7 03-31-2012, 12:23 AM

With my 02 3.0l reg cab, I had a bucking problem whenever I reached higher rpms. Keep in mind I had less than 100k on it at the time but this is a long shot: turns out, the yoke of my drive shaft was kinda hanging out of the tail shaft of the transmission. The seal had come loose and in the process I was loosing all my transfer fluid. Once I replaced the yoke and seal, which had been majorly heat worn from the friction, and topped off the trans fluid, no more bucking.
I'm sure you looked under there and checked your transfer fluid already, but just a thought.

glindy · #8 03-31-2012, 06:43 PM

Nick,
I used my scan tool to reset the ecm,won't this do the same? Anyway the misfires on 5/6 came back as well as lean bank2 code. So I went ahead and picked up a new coil as spark looked weak when I visually checked it on 5/6. Runs better but still shakes. So its got 65psi at the rail,has fire,injectors ohmed at 15,and I even put a new one on 5, compression is ~150. But still misses on 5/6 and has a small backfire when throttle tweaked at idle.Checked MAF and its voltage is good.
Looking for a noid lite to the inj wires,and NO auto parts has em,on line for $4. A Ford mech I worked with told me the 3.0 had a habit of breaking valve springs,which could have compression but still miss at low rpm,so then I'll pull the valve cover. He also said the ecm's drives do go out on these,maybe thats part of the over 3000 rpm bucking on the road,which is only supposed to govern P/N rpm? Need to find a cheap junkyard one to swap. After that not sure what else would do 2 cyl next to each other,intake leak,egr valve,sensor?

nicktheman2013 · #9 04-01-2012, 06:49 AM

Yes a scan tool will do the same. But that is a mystery. You've checked almost all the usuals and it may be an ECM drive cause on autos it will cut the fuel off when revving past 3k in park and nuetral. Not really sure this could cause a misfire but check your o2 sensor if you haven't already. as far as valve springs I say no go. Cause it only happends at 3k rpm. And on our trucks the valves open the same at 1k rpm as 5k rpm. Only difference is air fuel quantity.. if the springs where gone you wouldn't have those two cyls at all. And kinda a rare thing for both springs on two individual cyls to go bad at the same time. I just remembered hearing this somewhere but check for vacuum leaks. Get a can of ether (starting spray). Start the engine one day when it's cold and spray around the injectors and throttle body if the engine chokes or idle raises suddenly then you have a leak. Which can be a cause of a misfire. But be careful cause ether is highly flammable. That's why I say only do it on a cold engine

glindy · #10 04-01-2012, 07:31 PM

Next step,
Finally located noid light set and checked right bank,had to use gm style light as ford tbi did not fit harness. They all had a signal,not sure if it was timed right but they all did light up. Also pulled valves cover and checked springs,none was broken,but not sure on lifters.
So have fire,have compression and have signal,but still have misfires on check engine.
Now normally the engine causes an oxygen sensor to act up,are you saying the oxy sens goiing bad will actually cause misfires on 3.0?
If so I can swap bank 2 w/ bank 1 and see if misfires move.

I did spray manifold down with gumout and had no reaction for vacuum leak,looked for EGR valve but cannot locate it,any idea where they hid ir on 3.0?
Might go ahead and buy an ECM to see if it fixes it for ~$40.

Once I fix this miss I only need to replace the ball joints and 1 tire to pass inspection.

nicktheman2013 · #11 04-02-2012, 10:15 AM

A o2 sensor going out can throw allot off. I say it's worth a try. Did you run the engine with the valve cover off was everything going as it should? Good movement no tapping? But I've beer had a problem with the EGR and I have no knowledge of its location but did you check the PCV? it should be on the left side valve cover and have a hose sorta around it

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Never* but that's good I've luckyly had no problems with ball joints or anything the really only thing wrong with my truck is my pressure plate and clutch there getting weak but they've lasted the life of the truck. These rangers are tough.

glindy · #12 04-03-2012, 06:47 PM

the 2002 ranger has no egr valve.
only the 2.3 and 4.0 have them in 02

nicktheman2013 · #13 04-03-2012, 07:08 PM

Is it still showing a misfire and performing rough? idont remember you mentioning changing the coil packs. I recently viewed a thread that involved a misfire and it was because of the coil packs. He had changed the plugs cables and everything but not coil packs

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Lol well I don't think in 2001 the 3.0 had a EGR either cause I've never had a problem with it.

glindy · #14 04-04-2012, 07:19 PM

Think I located it.
After doing the coil pac,good noid light,fuel pressure,compression,valve springs,Maf voltage, etc pretty well narrowed itt down to a vacuum leak,OXY,cat.

Did a vaccuum test and was only ~12 no where near 17 min needed. Then pulled bank 2 Oxy and it was black,disconnected the maf for default. Started truck and I could hear the back pressure,it already started running better. Pulled the left cat manifold loose and ran it. No more misfires,quick reaction up up to governed 3000rpm,vaccuum went up to ~18, just some codes for maf,oxy,etc being disconnected. Reconnected maf,still ran smooth with just missing left cat code. So I'm thinking a new front cat,oxy should fix all misfires.

nicktheman2013 · #15 04-05-2012, 10:46 AM

Sounds good. Let us know how it goes