fuel and throttle power loss

1,700

Asked by Patrick Feb 26, 2016 at 07:01 PM about the 1994 Dodge RAM 2500 Laramie SLT LB RWD

Question type: Maintenance & Repair

Loss of power after warm up. Sounds
like engine gasping for air...definitely
stops combustion at twenty percent
throttle. No clogged Cat. New plugs.
New air filter. Injectors clean. New
TPS...MAP...IAC. Before I changed
plugs and removed cat no codes. Cat
is replaced...10000 miles.on
pump.filter in tank with pump. I am
now getting codes for MAP, TPS, and
o2 sensor. What is the problem? Has
standard 5 speed tranny. Idles nice.
Starts without problem. Doesn't die.
But starts puking under driving load.
Won't go up hill. Sputters and bogs on
straightaway. Anybody...give me a
viable answer. I am losing money cuz I
can't work without it.

33 Answers

220,505

Sounds like a vacuum leak, snug up the intake manifold, look for bad vacuum lines, PCV Valve, & EGR Valve and system components.

20 people found this helpful.
Best Answer Mark helpful
1,880

Faulty ground connection somewhere in your instrument panel causing a loss of power, or a dead short causing a cyclic loss of power to either the IAC or the injector circuits, especially under load...... Just my suggestion...... Cheap fix, but one of the worst headaches you can possibly get..... If you own a car and have to sometimes work on it yourself, buy a Chilton's or Haynes manual for it. Either at O'Reilly's or Autozone. Make certain you get the one that includes your own vehicle in it.

30 people found this helpful.
1,700

Rowefast...that's the only answer I haven't heard. Thanks I will check thatvout

5 people found this helpful.
1,880

I'm including a scanned copy of the wiring diagram from my Chilton's manual, colorized and a little bit modified for myself. .....Notice how every one of the symptoms described by anyone in relation to this same problem can be caused by an incorrect signal coming from the cluster to the ECM. I haven't yet gotten around to locating my ground because I've been busy modifying the diagrams to enable me to better understand them...... In "my" case there are multiple incorrect readings in the gages. I think I'm justified in at least checking out that possibility before shelling out any more money on guess work......Especially in consideration of the clear fact that everyone's guess on the solution thus far has "NOT BEEN CORRECT." And you can well believe that I have tried at least 90 percent of them, and none of them worked. Maybe I'm wrong. I'm certainly not a mechanic. But damn if I don't believe that I'm learning to be one. As much work as I've done on this truck, when I "thought" that a good mechanic who I was going to be helping change the block out and all the rest of the junk that wound up getting done. He liked to disappear, when I had no idea in hades what I was doing...... Except for that manual, which helped me, except in a couple of things that I could complain about, but it wouldn't do me any good to complain, cause Chilton's wouldn't listen. I need to get off this and go pull that dash to see whether or not I'm full of crap about my, and it is, unprofessional guess.

9 people found this helpful.
1,700

Today I checked and double checked everything. Each time, clearing codes from PCM. Found my evap line to engine not even connected at canister. So everything back in place...pcv cleaned and rattles just nicely. Start engine...go down Street 200 feet...start having a case of constipated diarrhea, puking at the hill, and coughing like a dying old lady what smokes three packs a day. Idles nice in the driveway.

22 people found this helpful.
220,505

Thinking it is running out of gas. What about the fuel pressure regulator? I see you replaced the fuel pump.

5 people found this helpful.
220,505

You may also want to do a fuel pressure bleed down test.

6 people found this helpful.
1,700

Came with new one...clear and clean. But the bleed down...that is easy one. On the rail where I did pressure check. Does engine need to be running during bleed down?

8 people found this helpful.
220,505

No, the engine not running, just hook up the fuel pressure gauge, cycle the key to build up the pressure, key off, watch the gauge from the highest pressure reading, pressure should not drop more that 5 lbs. in 3 minutes. So what was your fuel pressure reading at idle?

11 people found this helpful.
1,700

Going to buy new pressure test kit today. Upon inspection of this one...found it has plugged check valve. Also occurred to me that collapsed or broken valve springs on one or both heads could cause the same symptoms. Going to remove valve covers and do some exploring. I noticed a clicking noise on passenger side of engine. At first I thought was air conditioning clutch. Removed clutch relay, air conditioner fuse, and disconnected sensor for relay. Clicking still there. Also looking into manifold temp sensor since it runs great for a few minutes then begins it's quarrle with me and my destination. Wish me luck...thanks Rowefast. I will let you know what I found.

8 people found this helpful.
1,700

Okay...new tester...Bosch...multi tester for cylinder compression as well. Goes up to 300 psi. 44 psi just keyed on. Idle 3 lb loss. Holds both pressure ranges and doesn't change but maybe 1 psi fluctuation at half throttle. Slight buildup when shut down. Maybe 2 psi. Ford mite have a better idea. Lol....have a chance to get 94 f250 King cab LB 4×4...351 cid auto for $750.00 163,000mi. Owner says tranny starting to slip. A new tranny in this town ...no problem.

5 people found this helpful.
1,700

Could just be torqued converter on that. I can get those online for $100.

4 people found this helpful.
220,505

So far the fuel pressure is sounding good. How much did the gauge drop in 3 minutes when you turned the key off? And Yes, that trany would be shot in that Ford, And if that is the 351M400 engine, That is gonna be shot as well!

4 people found this helpful.
220,505

Well crap...Thats good....I'll have to read all this again and sleep on it.

4 people found this helpful.
60

I have an Dodge Ram 2004 2500 diésel runs good on 60 mph but over 75 mph start loosing boost can’t someone have any idea what can caused this. I ready remplace the selenoide and the map sensor but still the same

6 people found this helpful.
90

i have the same problem with my 98 dodge 2500 pick up v10. did you ever figure it out patrick. perfect descriptions. i have also changed many things chasing the problem but there it is everytime i fix something it still lingers around messing up an already low gas mileage only difference i here what sounds like spark knocking and a rolling muffler crackle. Please help.

9 people found this helpful.
20

Check for water in the air filter housing if there is any could be affecting map sensor it's a shot in the dark but I had same issues water in air filter box from high water splashed up on map sensor causing it to fault I drained filter housing used air compressor to blow out map sensor and housing were it's located and have never had an issue again it was on a g6 would start and run fine for about 5 minutes then would have same symptoms you described

2 people found this helpful.
60

I have a 2001 dodge 2500 with the V10 that loses power runs like a v6. Lol during rain and after rain. It idles fine but cant give it any throttle or it will just bog like its choking. Will still accelerate but just doggs bad. Any ideas? Im thinking electrical but im new to the V10. Replaced CPS. And fixed ground bank under the battery. Also under heavy acceleration on inclines the climate control in cab changes to defrost.

6 people found this helpful.
40

have dodge 2500 4x4 losse power got chk eng code p0300,3003,3004 MISFIRE changed plugs wires cap rotor still no power wrench found head gasket leak will keep u all updated

4 people found this helpful.
140

I have a 2004 Dodge Ram 1500, have had both throttle loss and shutting off at any given time. The shutting down was cured by replacing the ignition switch, and the loss of power was cured by replacing the APP sensor. Both are easy to do, on the APP sensor you may need a wiring diagram as my original sensor had a flat six connection and the flat six is no longer made, replaced it with a stacked three.

6 people found this helpful.
60

Well, let me join in...with a 2002 5.9L auto. 23,000 actual miles. snowplow truck..runs sweet at idle...drive and it lacks power, takes so long to shift into second ( a lil better if I ease up on the gas and help the shift) then a hard time getting to 50 mph. replaced fuel pump and plugs, fuel system cleaning, ran all fuel out and put new fuel in. wires, cap, rotor only 3000 miles on it. ????? ran fine up until 1 day , then it all started to go to hell.

6 people found this helpful.
1,880

I AM NOT A MECHANIC, but I feel like one after doing everything I wound up doing with my 94 C-1500......And an 02 is a whole lot different from the 94 that I installed a completely rebuilt ...top to bottom-front to back... 350 in it. The truck is now parked and started routinely, and, driven around my neighborhood, with a glitch in............ the transmission.........I'm just saving the truck with the rebuilt 350 until the one I bought to replace it blows up, when I'll swap the engine to the truck with a good transmission........It SOUNDS LIKE you might have trash in your tranny that interferes with the operation of the solenoids.....Just something you might want to investigate.....Good luck

4 people found this helpful.
50

I would guess the catalytic converter is plugged

4 people found this helpful.
50

I agree the catalytic converter sounds plugged you can test that by removing the O2 sensor and giving a vent path and try and your run test again.

1 people found this helpful.
50

Install the back pressure Gage in the O 2 sensor before the cat All the way up to 3000 RPM's And maybe 1 pound of back pressure So I would say the cat is clean open. I replace the distributor just because I had nothing better to do and nothing changed Newcap new rotor New plugs New air idle control valve Running out of ideas

5 people found this helpful.

I have a similar problem, P2100 code along with P2106 limp-in-mode caused perhaps by the first code. Was idling just fine, took it down the road, backfired 1 time and lost power and struggled to stay running. No other engine noice, and the back fire was from exhaust. P2100 mentions throttle motor control failure, APP, PCM, and wiring issue. I have an odd anomoly as well regarding the overhead interior lights. When power is turned on they do not go out, when key is turned off or out of ignition they dim to the point they are barely noticeable. I figure it is a bad ground or a short between the ECM and the PCM. Any thoughts since last replies?

I have a similar problem, P2100 code along with P2106 limp-in-mode caused perhaps by the first code. Was idling just fine, took it down the road, backfired 1 time and lost power and struggled to stay running. No other engine noice, and the back fire was from exhaust. P2100 mentions throttle motor control failure, APP, PCM, and wiring issue. I have an odd anomoly as well regarding the overhead interior lights. When power is turned on they do not go out, when key is turned off or out of ignition they dim to the point they are barely noticeable. I figure it is a bad ground or a short between the ECM and the PCM. Any thoughts since last replies?

30

My 04 QC Larime 5.7 (445k miles) had power issues for years. It would throw random codes at random time, sometimes it would drive perfect and other times it would puke fuel and fall on its face. At one point I was getting 6mpg going 70mph. Im pretty good at automotive diagnostics (ran a couple mechanics shops) and this took me way too long to figure out. One day I decided to check my battery voltage (12.8v), the body (9.9v), engine block (10.1v), either head (10.0v), valve covers/coil packs (9.6v), and transmission was (10.5v). I checked all this just a couple weeks after taking off the ground straps, inspecting/cleaning, and cleaning the mounting points with a wire wheel (strange). This is something I didn’t expect to find. I decided to run a secondary 0 gauge wire from the battery to the body and then got 12.8v. There was no change to any other components (even more strange). I then ran a second ground from the block to the body and got 12.8v, nothing else changed (wtf the entire engine should now be grounded). I ended up running a new ground to the battery to body, block to body, each head to body, valve covers to body, throttle body to body, and then transmission to block/body (2 separate new grounds). After all of this I was finally properly grounded and I no longer have random codes, fueling issues, dash lights dimming when using any electronics inside the cab, my subs and amp have never sounded better, transmission shifts firm/fast/easy, throttle response is instant and no longer need to go 3/4 throttle to shift out of overdrive, and best of all I got 16.3MPG average at 75MPH!! The best I ever got before this was 11mpg and it was extremely hard to keep up to speed and don’t get my started on trying to go up a small incline. Needless to say if someone told me it was a ground issue I would’ve told them to “go home, you’re drunk!”. After 5 years of replacing nearly everything on my truck I was able to fix it for free with wiring I had laying around in the garage. Grab a multimeter, get your reference voltage (positive and negative on battery), keep the positive on the battery and start checking everything!

3 people found this helpful.

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