93 Dakota 5.2L high idle

[Bartman70]

I recently purchased a 93 Dakota 5.2l v8 2wd xt-cab with over 200,000 miles on it.The only things that don't work on her are the cruise control and the o/d.Mods include dual headers,heavy duty battery,coil pack and k&n lifetime filter. When I bought the truck it was reading a 12 and a 32 on the key turn diagnostic check but it was driving fine for the first or so.I used a spray engine cleaner making sure to avoid any electrical connections and throttle body.I noticed a major build up of gunk on the tb valves so I used a spray tb cleaner to remove it. Problems: I noticed after the cleaning that she was idling high around 1000,1100 rpm in park and 800 in gear.200 rpm less when the a/c is on. Also, while driving I hit around 20-25 miles an hour and I can take my foot off of the gas and it maintains that speed.The idle doesn't change cold or hot.The temp gauge never goes above 1/4 until she has been running for a long time(over 20 minutes). I have replaced the IAC(thoroughly cleaning the port before installation)TPS and Intake air sensor(disconnecting the battery prior)with no change. Questions: Is there a "shade tree" way to test the vacuum system for leaks other than spraying wd40 on the vac lines? Could the coolent temp sensor and switch cause the high idle? Are there any other issues that could cause these symptoms?

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[Crazy4x4RT]

I believe code 32 is EGR. That can cause you problems. You can try getting a vacuum guage and see where your at. Normal is around 18. You can also disconnect all vacuum lines from the engine and take a reading. Then plug all lines back in then see what numbers you get.

[Bartman70]

Thanks for replying, it was showing that code when I bought her and she was running fine then. Everything I've read says that the egr would cause rough and erratic idle not fast idle or hanging on the throttle while driving. Is it possible for these symptoms to take over a week to pop up? What is it about the egr that would cause high idle?

I just replaced the temp sensor,switch and tstat.All were in Very bad shape. I took her for a 15-20 minute spin but the problems are still there.

On another note, is it true that if you put her in gear and hold the brake in the engine will try to staul if there's a vac leak? It really feels like a vac leak but I can't seem to find it.

I just got this truck and she has so much potential.I can see what she'd be like with alittle work.I really appreciate any input you may have and I'm sorry for having so many questions.I guess I've already kinda bonded to her and it's very frustrating when she isn't doing well.

work performed so far:
replaced pcv valve
replaced tps
replaced iac
replaced air intake sensor
replaced temp sens and switch
replaced tstat
banged head against the wall repeatedly

On the plus side, everything that I have done REALLY needed to be done and every step has made her run better.

[skyshark186]

May or may not help but the hanging throttle caught my attention. Spray some good lubricant on the throttle cable and work it a bunch of times. Could be that the cable is getting caught somewhere in the sleve(usually right at the end), and it it causing both problems. My bronco had a similar issue, only it tended to get stuck at full throttle....and with a chipped/modded 351 and 4.56 gears thats a very very bad thing.

[95_318SLT]

Here is what the FSM says about the EGR system:

EGR SYSTEM OPERATION—3.9L AND 5.2L ENGINES

The system consists of:

An EGR valve assembly (Figs. 8 or 9) mounted to the intake manifold.

An EGR valve control containing a combination back-pressure transducer and an electric vacuum solenoid (Figs. 8 and 9).

The powertrain control module (PCM) to control the electric solenoid portion of the valve control.
An EGR tube (Fig. 10) connecting a passage in the intake manifold (near the EGR valve) to the rear of the right exhaust manifold.

Hoses to connect the various components.

When the PCM removes the ground signal to the electric solenoid portion of the valve control, EGR system operation starts to occur. The PCM will monitor and determine when to supply and remove this ground signal depending on certain engine temperatures, throttle positions and other engine operating conditions.

If the electrical connector to the EGR valve control is disconnected, or the electrical signal is lost, the EGR valve will operate at all times. This may result in; poor engine performance, rough idle speed and reduced driveability during certain operating conditions.

The EGR valve control also contains an internal pressure-type transducer (Fig. 9). This transducer portion of the valve control is operated by exhaust back-pressure from the EGR valve. Exhaust is delivered to the EGR valve through the metal EGR tube (Fig. 10). This connects it to the rear of the right exhaust manifold. A rubber hose connects the backpressure fitting on the EGR valve to the backpressure fitting on the valve control (Fig. 9). When the ground signal is removed from the electric portion of the valve control (solenoid is not ener

gized), and exhaust gas back-pressure entering the

EGR valve inlet is high enough, back-pressure is supplied to the valve control. It then holds the bleed valve in the transducer closed. This allows engine vacuum to flow through the EGR valve control to activate and operate the EGR valve for exhaust gas recirculation. If back-pressure is not strong enough to close the bleed valve in the transducer, the valve control will bleed off engine vacuum preventing EGR valve operation. The transducer measures and uses this exhaust back-pressure signal from the EGR valve to regulate and provide the correct amount of exhaust gas recirculation under all conditions.

Exhaust gas recirculation will begin in this order when:

• The powertrain control module (PCM) determines that EGR system operation is necessary.
• The electrical portion of the EGR valve control is not energized (grounded) by the PCM.
• Exhaust back-pressure entering the transducer in the EGR valve control is strong enough to close its bleed valve.
• Engine vacuum is passed through the EGR valve control to the EGR valve.
• The inlet seat (poppet valve) at the bottom of the EGR valve opens to dilute and recirculate exhaust gas back into the intake manifold.

For more information, also refer to Open Loop/Closed Loop Modes of Operation in the Multi-Port Fuel Injection section of Group 14, Fuel Systems for 3.9L/5.2L engines.

[Bartman70]

Wow!! Ok, so it is quite possible that the egr is causing my problem.Is there any way to clean it or bypass it without gumming up the works?

That was the last thing I'd think of because, like I said, it was blowing that code before and the truck was driving perfect.