1985 Ford Bronco Engine or Tranny

SEMPERGUMBI23

MEMBER
1985 FORD BRONCO

Engine Performance problem
1985 Ford Bronco V8 Four Wheel Drive Automatic rolled miles

Engine runs a little rough needs some tuning. It runs strong through 1st and 2nd, but after shifting to third it just stutters and shakes. I cant raise the rpms (unless it downshifts) or increase speed (aprox. 25 MPH). Changed the harmonic balancer because it was wobling, no change. The tranny fluid is slightly high but is not excessively dirty. It has new cap + rotor, plugs and wires. Also changed the fuel filter because the seal was leaking. Don't know where else to start.

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,217 POSTS

Have you checked fuel pump pressure and volumn? Also, have you changed the fuel filter? Finally, does it seem like there is proper back pressure from the exhaust? The catylatic converter may be starting to plug.

Let me know.
Joe

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Thursday, June 4th, 2009 AT 10:47 PM

SEMPERGUMBI23

MEMBER
2 POSTS

Thanks for your reply. I just changed the fuel filter and the fuel pump is working fine. Didn't think the catalyc converter could cause that but I think that could be it. I got the timing right and fixed some vaccum leaks. So now it's accelerating after shifting to third, but still pretty shaky. I had a friend suggest the EGR valve, but at 215 bucks a pop I'd like to know before swapping it out. I'll try runnin just headers around the block to see if it is the cats. Thanks again man.

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Friday, June 5th, 2009 AT 12:39 AM

JACOBANDNICKOLAS

MECHANIC
108,217 POSTS

Rather than replacing the EGR, remove it and make sure it doesn't have a build up of carbon in it or the intake. Make sure the valve moves under vacuum and just give it a good cleaning making sure the valve opens and shuts.

Believe me, I couldn't throw away 215 dollares either.

Joe

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Friday, June 5th, 2009 AT 11:23 AM