I have a 91 Plymouth Voyager with a 3.0L. Just today it started losing power when I was accelerating, the more/harder I pressed the gas pedal the more power it seemed to lose. Seems like if I was to hold it to the floor it would probably backfire but I didn't want to try it. When I did push it to the floor for a quick second or two it would lose all power completely, but If I only pressed the gas say a quarter inch or so it would drive ok but I could not give it any more gas then that. It seems to be ok when I first start it but after about 5 or so minutes of driving this will start everytime. I just bought this a week ago and it seemed ok until now except for a rough idle, almost like a misfire. Here is what I have changed in the last week to try and fix the misfire symptoms.

Changed spark plugs, wires, distributor and coil
Changed PCV and hose
Changed Map sensor
Checked for spark on all plugs – Good
Changed Fuel pump
Changed Air filter
Changed computer

The last things I changed before this started happening was the map sensor and coil, I have since changed them back to see if that wasn't the problem but it is still the same. I am preparing to swap the fuel injectors with a known working set from my friends van. I am also going to change the fuel filter, but I cannot see this being the problem as it seems to me that it is only happening after it warms up, say 5 or so minutes into driving. If anyone has any ideas please let me hear them. :sly:

you are going to change fuel filter which would be my first guess you may also want to check for contaminated fuel wheh you do turn the filter upside down in a glass and see if it has water or other contaminants?

sounds like you have a badly clogged catalytic converter. When cats plug up, you'll have no power and have a top speed of about 35 MPH.

When I change the fuel filter I am going to let a liter or two of gas run into a container from the line before I put the filter on and reconnect the lines just to see if there isn't something between the fuel pump filter and the inline filter which was slowly working its way up the line to the inline filter as I was driving. I will also turn the old one upside down and have a look for dirt and the like. I'll take her for a run and see if she feels better. If not i'll move onto the fuel injectors (wouldn't hurt to try I think as it is only about an hours work) The ones I took from my friends van are all shiney and new looking as they were just power flushed and cleaned a month ago, right before his head gasket blew. I was also thinking the cat convertor but usually you will get the rotten egg smell when that plugs up and it would get very hot, neither of the two I am seeing, but that doesn't mean it isn't happening. I am also thinking maybe carbon fouled valves but thats another days work..lol. I'll keep ya's posted on the outcome of todays events. Thanks for the replies, much appreciated.

Well I changed the fuel filter and the gas in it did look a little brown. I tried blowing through the old one and could barely if at all blow through it so I thought , uh huh, this is the problem, NOPE. I put the new one on and took it for a drive and the same thing happened, it took about 10 minutes before it started but it did start doing it again, just as bad. I checked the Cat convertor and the last owner already had it cut open to remove the guts and welded back in place so that isn't it either. I am now in the process of swapping the fuel injectors, i'll be back to report in an hour or so on how this worked out. Any more ideas? Please add them. Thanks.

Well I finally got the injectors replaced and the van seems pretty much the same as before I started it, if not a little worse. Now I am getting error code 26 and the check engine light won't go off, I looked it up and it shows as an injector error stating that the said injector isn't getting enough power. Any ideas on what to try next (not counting checking the injectors again). Still seems like its misfiring or stumbling and not all of its power is there. Drive it for 5 to 10 minutes and can't give it gas any more as it loses more power with the more gas I give it. Cmon people, help me out here.

Ok, I just finished giving her a compression test,the results. Cyl # 1 - 190
Cyl # 2 - 215
Cyl # 3 - 50
Cyl # 4 - 192
Cyl # 5 - 190
Cyl # 6 - 190

So I have 2 problems so far, the worst one being Cyl # 3. I will do a wet compression test tomorrow to see if it rises this Cyl compression ( as it is now 2:50 am and I have been at this van for near 15 hours today). I'll update more after this test. Any more ideas, suggestions or comments, feel free to let me hear them, I am more then open to comments at this point.

Well I ran the wet compression test today and the cylinder never rose in pressure at all so I am thinking possible valve problems at this point. Any other ideas before I start tearing this motor to the valves?

could it be possible that you have a blown head gasket? If not, I still believe you should check out that catalytic converter by doing a backpressure test on it. Connect a vacuum gauge to your intake manifold run the engine up to about 2,000 RPM, and let it go, it you see the gauge spike up and go back down, you've got serious backpressure caused by a bad catalytic converter. Though that doesn't explain 100% the low compression in cylinder #3, but the head gasket would cause the same thing.

Any more ideas, suggestions or comments, feel free to let me hear them, I am more then open to comments at this point.

Could be a lot of things, but since you've ruled out a lot I'd certainly try the 'extended' alternator test before I kept changing parts and ripping the engine apart.....

I was also thinking head gasket the whole time I have been testing this van but have no clues pointing to it yet, I have no white smoke, I have no water in the oil and vice-versa, Only one cylinder is low where it would usually show 2 in sequence.I am really not losing that much power. I know this still doesn't mean the gasket isn't gone but all signs are saying no so far. I was looking at the cat convertor and speaking with the previous owner, he mentioned that he had the convertor cut open and emptied out. I looked at it to make sure and sure enough I could see where there was a square cut out of it about 4 inches across and 6 inches long then that square was welded back into place. I am going to try the test mentioned just to make sure though, thanks for the idea.
I'm sorry but I failed to mention that I had tried the alternator test, twice actually, I even let it run for about 40 minutes at one point with fan on high, high beams and hazzards on and dome lights on, it never dropped below 13.9 once, not bad I think :). So this is where I stand at the moment. Just to recap, this is what I have done so far.

Swapped spark plugs, wires, distributor and coil
PCV and hose
Map sensor 3X
Checked for spark – Good
Changed Fuel pump 2X
Changed Air filter
Checked timing
Changed computer
Changed FI’s
Checked fuel pressure 2X
Checked alternator 2X
Changed fuel filter & gas

I am now in the process of locating a dealer with parts not too expensive as I plan on changing all valves while I have it open (as was mentioned before) and the seats, maybe even the guides, i'll see when I get there..lol
It's just these little things that bug me like the constant miss and knowing I could be getting better miliage. I think I have it figured out but am still open to suggestions. I think the problem of when it gets warm and starts losing a lot of power when I hit the gas is related to the O2 Sensor which I plan on replacing today to see, as it only does this once it warms up, and what a coincidence, the O2 sensors only starts working when it to gets warmed up.lol.
The miss I am thinking is a stuck or bent valve, thats where everything is pointing now. I will keep posting and updating as things continue, I know I love to see when people follow through with posts to see the outcome and cause and fix of their problems (I wish all people did this) and also in case someone else gets/has this problem it may help them to fix theirs. Ah well another day, another repair..lol
Thanks again people for the replies and suggestions, I appreciate all of them a lot.

hate to be a spoil sport and ruin your fun, but wasnt it right about around that year that crysler had fuel sending unit problems ?dealing with corrosion and all? that wont help your lack of compression in one cylinder but if car looses power after five or ten minutes and it isnt cat as discussed previously would point me to doing fuel pressure test? just to rule that out i rather test than replace parts myself

Well I just put on a brand new O2 sensor and reset the computer. Am on my way out to test drive it again but I seriously don't think will help the power loss proble. If it doesn't I am going to try changing the EGR. If that doesn't help then its back to fuel again. I will try a fuel pressure test where my fuel pump is so loud the last few days. Thanks for the input on the sending unit problems, I'll have to look there also I suppose if this doesn't work. Now to find me a pressure tester. Anyone know what a normal reading should be with these vehicles when doing a vaccume test? Thanks again for the replies and ideas, I WILL FIND THE PROBLEM IF IT KILLS ME :banghead: Little does the van know, the more PO off it makes me, the more determined and stubborn I get..lol. I will report back soon.

That was a quick test drive..lol. Didn't change a thing at all. :(
Ah well, now to find a fuel pressure tester. I'll keep ya's informed.

Ok so I went to the gas station today and decided to fill er up for the first time ( due to gas prices going up again and also to see if would help the problem in any way). Gas started pouring from the top of the tank when it hit full but im pretty sure I know why, I think I may not have tightened the vent hose which runs paralell with the filler hose, where it connects just above the tank. Would this maybe cause a pressure issue and have something to do with the problem of no power? I really can't see that as it only happens when its hot. Now the van did seem to drive better after filling up but not 100%. Just seemed to take longer for the power loss problem to start. And this time it didn't do it the same way as it was, as when I would try to give it a good shot of gas it wiuld just bog right down and all power lost. This time when I put it to the floor while doing about 80km, the motor seemed like it was getting the power as it reved up to about 4000 rpm but it was like the power wasn't getting to the tires, now I'm thinking transmission. WHat do you guys think about this now? I am still going to try checking the EGR later today when I get time. I was just planning on pulling the vacume line off it and drive it that way for a bit to see if that changed anything, not sure what else to do with the egr after that, maybe remove it completly. I have heard of tests with a hand pump but I don't have one to try it. I do have a vacume tester though. WOuld this be any good for testing the EGR?

Just scratching, and shaking my head over this stupid problem. I have a 1996 SE 3.0....Thanks for going into detail as far as what you've done and what you haven't etc....it's much appreciated seeing as I have the exact same problem with my ride.

I brought the car into the dealership and they noticed one piston is misfireing and that's gonna cost atleast $1200, i think it was the fourth...it's already reaching 300,000km so right now this problem is more of an inconvenience.

While driving on the highway. It randomly cuts out, and the more i open the throttle, the more it seems to choke it'self, unless i give it a small ammount of gas, there seems to be some acceleration..meanwhile trucks fly past me, and my life flashes before my eyes lol....let me know if you've had any success with this problem.

as of now, if i keep gassing it while the power drops...usually it takes 20-30 seconds before the power restors it'self.

cheers

p.s.

If it's of any use, when the power does cut off - the dashboard acts up simaltaniously (speedometer drops to zero and the milage display freezes to whereever it left off and doesn't accumulate any kilometers untill the car is restarted...could be a fuse but i doiubt it's that simple....computer glitch most likely. thanks again

Cheers

The engine is in "Torque Management" mode when you are moving less than 7 miles per hour. I wonder if your speed sensor is bad and when it cuts out, the computer thinks you have stopped and is limiting RPM and power.

very interesting idea, I'd swear it's a faulty sensor or component chip considering the lengths Rottweiler28 went to in order to address this problem...my stupid van lost power three times tonight on the highway, and it only lasted for a good 30 seconds at each interval. I was lucky enough to maintain 90km/hr while this happened.