Im having this problem too. About 2300-2700rpms the motor doesnt have any power and bucks and dont wanna rev, but after those valuse, she comes alive.

With the plate between the EGR and intake, do you cap off the Green vac line also? I am installing a set of headers with no provision for the EGR tube and was wondering what to do with it...

 

Yes, you have to cap off the green vac line.

 

I'm having the same problem with a 1987 F-150 L6 300. I plugged the EGR hose and it helped a little bit for a little while, but I still have the problem. I'm thinking the next step is the fuel injectors. Anyone else think that's my next step? Or should I try something else?

 

My 300ci, 6 cyc, 1990, I have noticed that the plugs and distributor cap have to be in good shape. Use only Motocraft plugs and cap&rotor. The coil wire post was corroded also. What helped the most for me was plugging the EGR vacuum line. Change the fuel filter and run Chevron Techtron cleaner in the fuel for a few tanks.

 

I've had the same problem as every one else, bucking and jumping at low rpm's.As in city driving. Pulled off the vac line and taped it off. Smoothed right out. Check engine light came on and stayed on. Tried to take the EGR valve off but was afraid of snapping off a bolt. They wouldn't budge. I'm going to try spraying some penetrating oil on them and letting it soak in. I'd like to get the restrictor plate in there so the light goes out. THANKS for the great advise. Should of looked here first. .03 cents worth of tape compared to new fuel filter, cap, rotor, wires and plugs.

 

Does anyone have any plans for the restrictor plate block-off, I understand it limits the amount of ERG gas that flows. I can not remove the EGR valve because it will not pass smog here in California. Or what is the new size of the EGR flow hole in the gasket or new block off plate?

 

Give this a try instead of removing the EGR valve if you can:

Loosen the tube nut that goes to the EGR valve and slip in a fender washer (IIRC the diameter of the washer is 3/4") with a 1/8th inch hole in it between the EGR tube and the EGR valve and then SNUG the tube nut back up.

DO NOT OVERTIGHTEN THE TUBE NUT !!!

What you'll be doing is putting in a restrictor before/upstream of the EGR valve instead of after/downstream of the EGR valve.

I just smogged my truck and removed the washer for the test.
Got home, let the engine cool down a bit, replaced the washer and I'm good for another 2 years !!!

Simple, effective, no snapped off bolts.

Good luck,

Bob

 

I've had this problem as long as I've had the truck (8 yrs). I had just about resigned myself to life with it. I put in the aluminum restrictor plate and it runs great.
'89 F150 CUSTOM. 60.000 MILES.

 

I ended up using a 5/8 freeze plug with a 1/8 hole drilled in the middle between the EGR and the intake. Basically same as the above method, but ive had my EGR off before and had no fear in busting bolts. Truck runs smooth now. But this is on my 5.8L.. still applies though

 

Thanks for the idea Truckin Bob. I couldn't get that nut to move either. Kinda afraid of breaking something. I sprayed it down too. Maybe it will soak in. I'll try spraying it for a few days and see what happens.
I wondered if a little heat on the nut would help?

 

Yes, it will.

I'd give it a good soaking ( I used PB Blaster on mine ) then heat by getting the egr system good and hot (run above 2000 rpm for 4-5 minutes or more) and then gently see if it'll break loose.
If not, re-soak, try again, re-soak, try again.
It'll eventually let go.

Be careful of spraying anything on hot parts.

Use anti-seize to re-assemble if and when it breaks loose !!!

Good Luck !!!

Bob

 

Good thinking on the anti seize. I put that stuff on every thing. It'll save your a$$ on alternator bolts.

 

Paul, You're a genius. Thank you ever so much for your posts on the bucking/intermitent missing of a Ford 4.9L I6 engine. I spent $309.76 in parts trying to beat that problem in the 1990 truck I bought a few months ago. First I took it to the mechanic I've used on things that were beyond my capabilities and he was still baffled after I spent $200.00 with him on an injector cleaning service that I probably didn't need either. Just put in the injector plate an hour or so ago and put the old EGR valve and sensor back in. Took her out for a 20 mile ride. Ran great. No missing, no bucking. Thanks again.
rudyrides

 

Well I found my problem for the hesitation... Long story short, my MSD Ignition Blaster was causing the problem. I disconnected the Blaster and ran straight off the coil and the hesitation went away. I found a lot of corrosion on the wire ends too. You guys may want to look at your wires going to the coil.

 

Holy ancient thread.

The computer expects some amount of EGR. Without it, you run lean. Too much EGR, and the engine starves for oxygen. The 1/8" plate is an in-between value that the computer is able to cope with under all conditions, probably using O2 sensor trim.

If you disconnect the EGR vacuum line, the CEL will light- the computer does a test where it opens the EGR and looks for a change in air/fuel ratio. I don't know if the light still comes on with the 1/8" plate. I imagine it would, if the valve is totally defective.