1987 Ford Ranger 2.9L Sporadic engine mis-firing, idles ruff and then OK

I have a 1987 Ford Ranger and sometimes when you start it up (hot or cold) the engine runs so ruff that it feels like only three of the six plugs are firing. The engine shakes so hard that it feels like it's
going to jump right out of the truck. Then after a while it starts to run OK. Sometimes when you come to a stop sign, the engine dies. It usually starts right away and runs OK, but sometimes it doesn't. It has a manual trans, V6, 2.9L engine with twin gas tanks. The engine is fuel injected with electrical ignition. I keep the engine tuned and with regular oil changes. I just replaced the air filter, spark plug wires and distributor cap about 8 months ago. Twice I've added 'Heet' products to the gas tanks to get rid of any possible water in the gas. Also, added a product to try and clean out the fuel injectors. The other day it started and would not take the gas at all and the engine died each time. The battery finally died and had to put it on a battery charger. The next day it started like nothing was wrong. The truck never acts up when you are driving down the road at a constant speed or slowing down. Can you please help? Thanks! Rocky R.
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Uh.. did you change the plugs?
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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Backyard Mechanic wrote:

To Krusty OLD Geezer,
Yes, I always change the plugs when doing an engine tune-up. I even took the truck to the Ford dealer and they kept it for two days testing and trying to find out what was wrong. No luck, it just wouldn't act up when they had it for those days. I guess what I need is to find someone who has a Ranger or maybe any other vehicle that did the same and can let me know what they did to fix it. Thanks for your time anyway and I am trying to DEAL with it.
Rocky R.
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I am too lazy to look up and see if that is CFI (throttle body injection), which is it?
First thing I would do is get the ECM(PCM) codes read out. Get the codes not the description.
Then, if no codes, think about any other oddities, like how it idles when started and at stop signs, lights, etc. After making sure that the ISC/IAC/IABP _ different terms for same idle control valve -or motor- is working right.. clean or replace it. Move on to other culprits.
IOW - if engine racing, at any random times, may point to bad wiring grounding connections.
Another good place to start is the TPS (Throttle position sensor)... flaky return from this might cause PCM to think you are pumping the accel and will deliver more gas than needed through injectors. It is relatively inexpensive and easy to replace.. use Echlin, stay away from Wells brand.
Next is connections to ECT sensor.. then Fuel pressure regulator on the fuel rail.
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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