2000 Ford Ranger V6 4.0 will often chug or stutter while driving. It used to dies at stop signs and red lights constantly, but the stuttering while driving only began after 2 O2 sensors were replaced. We replaced the fuel filter, and a new fuel pump was installed last year. This mainly occurs about 2000 rpm, and it has a lot of chugging/ failure to accelerate normally at about 50mph. Some days, especially in wet weather, it drives dramatically worse, but for weeks sometimes you will have no problem whatsoever. I don't think this could be spark plugs or the transmission because it is intermittent.

SOURCE: multiple cylinder misfires

cross the wire, probably the firing order problem.

Did you change the distributor cap, sometimes the distributor cap inside cracked, you won't see it, take off the distributor cap, but you have to remember the wires' order, lightly drop the distributor cap see if you can hear the cracking noise.

Or during the dark night, get a dark place, start your engine,see if there is spark out, fix that, maybe your car will run better.

When I had my Union 76 service station, I have solved several cases like thiat.

I had a big Sun electronic scope from 1973 to 1984, during that time, something I could't ping point where the problem was, therfore I used many experience, maybe I am wrong, but you can try it, I like to try everything.

Hope this ccan help you, good luck.

Frank

SOURCE: car chugging

To determine what's wrong, u need to have the codes read. If the light is coming on, it is a signal that something is wrong w/ the emissions system. A code is stored in the cars computer that will indicate what the problem is. Most parts stores will read the stored engine codes for free. They plug a scan tool into a port under the dash to retrieve the code(s). Write them down, and ask what u should do to correct the problem. If u have any further questions after that, u can post them here. Let me know how u make out.

SOURCE: Power loss / low idle speed

This could be a multitude of things but my first suggestion would be to change the spark plugs. They are cheap and can be bought at any auto parts store.

SOURCE: 1994 ford ranger extended cab 6 cyl fuel injected 2 wheel drive automatic

This year of ranger had a few flaws, In one case, a break power booster was robbing the vacumm, you can test this by plugging it off and seeing the differance, but you will have limited brakes. This model year had a problem with a vacuum leak on the manifold. You can check these in many ways, but please don't use starting fluid. The rear of the manifold usually on the drivers side where it seals to the block.
Also, in 2 other cases a cracked head has gave me the same problem. It is caused from a loss of vacuum.

SOURCE: chugging and power lose

Major tune up and change the crank sensor and the camshaft sensor. Also look at the wire harnes for both they have a problem shorting out. Mostly the harness to the crank sensor at or above the oil filter. This wire shorts because of heat and needs to be rerouted and insulated. Also, make sure you have all your gaskets inside of the intake maniflods and throttle body is secure with no air leakes. Change all your senors on this car that seems to be the trouble with this car is the sensors........runjoe