I have an 89 F150 with a 300 6 cy with fuel injection. It has 200K miles on it. About 5K miles a go I had the injection system cleaned and fuel filter replaced and it fixed a bunch of problems but the computer showed that the O2 sensor was sluggish and the EGR valve was bad. It still ran good so I ignored those two issues. Now, 5000 miles or so later, it has started jerking and bucking at lower rpm's. I replaced the O2 sensor and EGR valve last night ($165 Ouch!!) and the problem is still there. There is no check engine light lit and I checked the plugs and they looked good. The plug wires, cap and rotor are newer and appear good. Also at an idle the rpm's fluctuate when cold and the engine seems to run rough when at a warm idle. Any ideas would be greatly appreciated. I had one person suggest that I plug off the vacuum hose to the EGR valve and see if it ran better and if it did then what ever is controlling the vacuum is causing the problem. I haven't done that yet.
Thanks guys!!!
I did a test of all cylinders and they were between 115-135 cfm or so. From what I understand that isn't bad as long as they are all close in the same range. I did this test before the fuel injections system was cleaned. Does not burn oil and oil appears clean and free from any water or anything.
How does the exhaust feel. Have some one rev it a little and put your hand over the pipe to see if it feels normal. Try to see if it is obstructed as the cats could be clogged. Check for a cracked dist cap or faulty wires. Check timing. Has the timing chain ever been replaced. Put on a timing light and look to see if the timing moves around it should not if it does the chain could be stretched.
Took the truck in to have it hooked up to the testing machine. All sensor look good. The mechanic again pointed to the injectors and said that since we cleaned them three months ago and now they are causing a problem again we should replace them. $400 I think I will try and do that myself. Napa has a shop that will remanufacter my old ones if I bring them in for $27 ea. Anyone know of the difficulty of removing the injectors out of a 300 6, any suggestions or hints would be greatly appreciated.
I have a 89 F150 with a 4.9 manual trans and dual tanks. the issue is after the truck runs fore about 10 min I get a soft hum from iside the cab ( have not been able to determine the location). as the truck runs the hum will get louder until it cuts in and out. At that time the emgine will skip and stop. This happens both at idel or running down the road. I have changed the Fuel pres reg. the external fuel pump and the fuel filter. I have not had any engine lights indictors. any ideas are welcome.
Try to duplicate the hum with it idling in your driveway, then try to find it. Try disconnecting or pinching off various rubber vacuum lines to check the effect. DON'T pinch the hard plastic ones, but plug the suction side of anything you disconnect.
This motor does not have a timing chain. The cam Gear and the crank gear mesh together, so no chain stretch possible. Could be slop in the gears, but not so much. I'd look at ignition. Mine was really bad for moisture in the cap. She'd buck like a Bronco, but I had an F150. hehehe
Take the Vac line off of the EGR. If the engine runs good then the EGR is bad, Or the cheaper fix, The vacuum control valve. Located in the middle of the block at the rear. You can follow the vac line around the rear of the motor to the controller. To test the vac control take the elect plug off of it, Start it up, If you still have vacuum at the EGR line, The vacuum control is bad. It sells for around $40.00.
Take the Vac line off of the EGR. If the engine runs good then the EGR is bad, Or the cheaper fix, The vacuum control valve. Located in the middle of the block at the rear. You can follow the vac line around the rear of the motor to the controller. To test the vac control take the elect plug off of it, Start it up, If you still have vacuum at the EGR line, The vacuum control is bad. It sells for around $40.00.
what the hell is giving you the idea that these are egr issues?
If its an EGR issue, and still getting flow efficiency codes, I would also clean the passage through the intake between the air stream and the EGR valve
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company
94 4x4 5.8 newly rebuilt 155000 miles we call it the white trash and 04 4.whatever 2x4 my wife drives it.
I think I will try and do that myself. Napa has a shop that will remanufacter my old ones if I bring them in for $27 ea. Anyone know of the difficulty of removing the injectors out of a 300 6, any suggestions or hints would be greatly appreciated.
Linear Mode
