I have a 1988 ford ranger with a 2.9l v6. a few days ago, driving to work, i stopped to buy a pack of smokes, and on my way out of the lot, the engine died quietly. started it back up with no problems and proceeded on my way. ever since then i have had a continuing problem with her running very rough at idle and having close to no power when accelerating. here is the question, as i stated it is running rough at a normal take off and idle, gurring acceleration and cruising it is also very rough, however when you get on it, she comes to life and runs fine, until you ease up and try to cruise. she acts as if she has no fire, but this is misleading as it does have great power at 3200+ rpm. i thought it may have been a fouled plug(s) so i replaced them, and while i was at it, the wires, cap, rotor, and ran an octane booster. this did nothing to help. i have noticed durring the "limp" acceleration and cruising, it billows black smoke like a chemical fire, until you gun it and the smoke stops. i know this is a fire issue, but i dont know where to go from here, if it were a bad ignition coil, wouldnt the problem exsist durring the entire rpm range? i am at a loss and do not want to go the route of buy everything and hope for the best. any advise would be greatly appreciated.
First I know nothing about how Fords work.
That said it sounds like the engine doesn't know the difference between idle and wide open and its flooding at lower RPMs. Do the 2.9 use a tps or is it a maf system? Check and make sure all of your vacuum lines and electrical connectors are hooked up. As it came on sudden and not over a period of time it sounds like something came unplugged and didn't just go out. I once worked on a car that had a temperature sensor go bad and it made the car run bad because it was dumping tons of fuel.
In my opinion that is where I would start looking.
2.9's have a TPS sensor.. check the codes, with that problem, it'll have at least 1 for you, regardless of the CEL..... very possible the fuel preassure reguator ruptured, sucking raw gas in from the vac hose, this would cause it to go limp in mode but run ok at higher rpm... the ruptured regulator is common problem.. mine had that problem when I bought it ( '92 2.9 ) and mine had a bad stumble, but also started hard.. was $125 for the reg
press. reg is good, no vaccum leaks, new fuel filter. compression on all cylinders is between 45-50lbs. thought about removing the distributor and rebuilding it with a new pick up coil and ignition control module, would like to bounce this idea off some pros with more expierence than myself.