99 isuzu Rodeo V6 idles at 2500 all the time. No adjustments have been made on it but... When you hit accelarator it will drop RPM for a short period of time,but does shoot back up almost instantly. Any Ideas? Thanks

it's no jeep,. sorry.
Rodeo run 3 or 4 v6 engines.
so what is the displacment and best is to say what country,.
are you in canada?
we are a USA forum., so...??
the fsm book covers this.
as does alldata.com
Isuzu is dead here in uSA, so they cant sell you a book.

in usa its a Gen 2 Rodeo
here are the 32 v6s in gen2

• 3.2 L 6VD1 V6 (gasoline)
• 3.5 L 6VE1W V6 (gasoline)

most common here is the 6vd1 in usa. alldata.com covers ours.
so lets google that.
using real names for engines makes google search HIT.
true for all cars. all engines.
so i type for you, and bingo, hits a many. even a video. hark.

https://www.google.com/webhp?gws_rd=ssl#q=isuzu++6vd1+timing+belt

fuel filter, fuel pump

which car is it?

problem with 1993 Geo Prizm '99 silverado 5.3 engin will not idle runs at 2500 rpm and drops down to 1000 rpm the back up to 2500 rpm -------------------------

There is a mechanism called the Idle Air Control Valve that is bolted to the throttle body with two bolts. It has an electrical connector plugged into the front of it. When that unit started going defective on my 97 Rodeo, sometimes the car would idle at 2500 RPM when the clutch was pushed in. Other times it stall when the clutch was pushed in. At the time (5 years ago) it cost $41 from Autozone to replace.

I had same problem with 99 Isuzu Rodeo LS 3.2 V6. Dealer couldn't find it and many, many other owners experienced same thing. finally found a post where a mechanic (non dealer) changed the idle air control valve. so i tried it, and after 3 years of dealing with the problem, it worked!!! part costs about $40 and very, very easy to change yourself. for the 99, its located in front of engine, so easy access. Good Luck

check vacuum leaks,throttle position sensor ect.sticking throttle cable?

Cams will point straight up to match marks on housing and crank will be at about 1 o'clock where mark on crank pulley will line up with mark on oil pump casing

Check the fuel pressure it could be the fuel pump or pressure regulator.

egr vlve itself will cause rough idling ,stalling,stumbles during accelaration,iwould take it off clean valve ports of carbon deposits,put it back on and see,egrs are exp.enough,and like ccn7 said sounds like tps problem,but usually they give a code

Good Day
Vale clearance cold
intake .006 in (.15 mm)
exhaust .010 in (.25 mm)

Timing
1. With transmission in Neutral or park, start engine and warm to normal operating temp. turn eng,and all accessories off. connect Tachometer. Connect timing light to no 1 spark plug wire.

2. Disconnect and plug fuel vapor canister purge hose and EGR vacuum hose. Start and ensure idle is 900 RPM. adjust idle as required. Check ignition timing ( 12 @ 900)

3. If adjustment is required, loosen distributor hold down bolt and turn until timing is within specification. Tighten distributor hold down bolt and recheck timing. adjust idle speed as required.

hope this helps

Cheers