High idle/surging when in foreward and reverse gears

[Rmc]

Bouncing speedo when moving or parked?

[RyanDS650X]

Both in park and in drive at a complete stop. When in drive and rolling it idles high enough to up shift without my foot on the gas.

[Rmc]

Test & clean the iac, do a resistance test on the tps.

http://www.fullsizebronco.com/forum/sho ... p?t=198462

[Silverslk]

Quick search

http://www.f150online.com/forums/v8-eng ... -idle.html

Last post says "stuck EGR, problem solved"

[RyanDS650X]

thanks for the help guys but ive ran through all those parts aswell as my mechanic. Voltage at TPS is .8 at idle and 4.5 WOT, EGR is working as it should also. I replaced the VSS sensor today, fired it up and she sounded nice and smooth... for 5 minutes. Im stuck.

[hobbyturnedobsession]

Its when your truck goes into closed loop. Check your wiring and your grounds.

[RyanDS650X]

VSS took a hit at some point. Installed a new one but didnt help.

[RyanDS650X]

Hunting idle after i installed the new VSS sensor.

[hobbyturnedobsession]

Mad sensor?

[hobbyturnedobsession]

Maf*

[RyanDS650X]

Ive cleaned it but it is just about the last original sensor on the fucking thing. Know how to test if its faulty??

[Rmc]

Any cel? Have you checked for air/vacuum leaks? Spray ether at all the seams and upper intake& lower intake manifold plenum seals. Hunting for proper fuel air ratio via readings from the 02 sensor can cause similar effects. You can also use salt water which causes a engine bog on the attempt to combust ( according to my mechanic buddy but I always use ether to cause a jump in rpm, I hate rusty shit as the after effect of saline). Recently I did the ether test and found nothing turns out it was sucking air from the valleys in the block so I couldn't find it until it was replaced. That on a 4.2v6 but similar condition was the intake leak result. Minus speedo pulsing.

[RyanDS650X]

No codes and no CEL. All upper and lower intake gaskes are brand new as of 3 days ago. Went around all over the engine bay with brake clean looking for vacuum leaks and nada... Weve gone through allllll these things over and over. Its a gremlin.

[Rmc]

In an obd2 it would give lean bankxxx if it was the case. May want to check the 02 sensor wires as well while your at it.

[RyanDS650X]

Hooked the diagnostic computer to the J3 port and watched the O2's go through their cycles and they are right next to eachother on the graph.

[Rmc]

Hmmm

[RyanDS650X]

I know man, thats all the responses ive been getting. Its a ghost that noone has seen before.

[hobbyturnedobsession]

I'd still swap out the idle air control valve and tps. I'd take em back and get new ones.

[Rmc]

I don't think it's a ghost I think it's 2 problems at once or the computer might be dammaged from a previous short some place.

[Rmc]

Iac good= 7-13 ohm range
Just had a thought. Have you cut a coke can up to make a sheetmetal block off gasket for the egr?