Engine rpms at 2500 all the time

iac motor could be bad. also check the fuel pressure regulator to make sure it isn't leaking fuel out of the vacuum connection and allowing it to **** back into the intake.

vacum leak will cause the high idle.with car running listen for suckin sound around intake.there may be vacum hose routing diagram on underside of hood.

had same problem on 74crewcab the vacumn line was tee d into another giving low vacumn . when it did reach sufficent pressure the trans would shift but the engine rpm was very hjgh and result was it slammed the trans in gear. Inspect your vacumn hose from modulator to the intake manifold/carb itcould be leaking or some one may have rerouted by accident.it must have a vacum draw equal to manifold pressure to shift in time with the actual rpms of the engine hope this helps...that it shifts at all makes me thinnk the modulator valve is working --just the vacumn line(s) arenot draw full manifold pressure

High rpms could be caused by an intake leak or vacume leak check your vacume lines maybe in the process of replacing your plugs you might have accidently damaged a vacume line.

How high do the RPMs go up? It could and usually is your idle air control valve(IAC). In the 940, it is not bolted into the intake, rather it bolted elsewhere underneath the intake and two rubber vacuum hoses connect it to the engine intake. If these hoses are ruptured, the your engine will rev up at idle. Also it could just be the IAC itself malfunctioning.

Sounds like a broken or torn vacum hose, pcv valve clogged, or bad Idle air control motor. Did you spray carb cleaner on vacum hoses or near the plastic intake., and did the motor rev up or down? Those codes represent a lean condition which means most like a vacum leak or clogged idle air motor. Sometimes the intake manifolds crack or the intake manifold gaskets crack. FInd that vacum leak or inpect iac motor

you have a vacume leak somewhere.check all of your vacume hoses for leaks.Injector seals can cause this too.Also intake gaskets could be leaking.Running to lean usually means the car is getting to much air coming in.To check leaks spray brake cleaner around the hoses and the bottom of your intake if the rpms change then you found a leak.

OK. Since you have had so much trouble lets check the dealer for an updated software calibration for the PCM (power train control module). Once we're sure there is no "fix" here lets talk about "lean" engine conditions. Lean means one of two things are wrong with the air fuel mixture (ideally 14.7 parts air to 1 part fuel). 1. Too much air -or- 2. Not enough fuel. If you access to a scan tool we need to look at fuel trims. With the engine warm look at this data on the scan tool. You have a "bank 1" and "bank 2" fuel trim data. Additionally, each bank has a long term and a short term value. With the Engine hot and at idle add the LT and ST trim value for bank1 and write it down...do the same for bank2. Repeat this step, for EACH bank with engine at 2500 RPM in park (hold at 2500 for at least 30 seconds so trims update). Now, you have the total trim values for each bank at idle and at 2500 RPM. What should the values be? Total trim +/- 5 is good, +/- 10 borderline any thing greater is code setting territory. If trim numbers are high at idle and in range at 2500 rpm you have a vacum leak behind the mass air flow sensor. Or a faulty MAF. Pay particular attention to the air inlet hose clamps behind (between MAF and engine) the MAF. Also use ford parts only.

Sounds like a major vacume leak, most likely the fittinng comming out of the intake for your power break booster or a break in the hose going to the break booster. In any case there is a major vacume leak.

CHECK FOR VACUME LEAKS,A PROPANE TORCH WITH A 3 FT PIECE OF HOSE ATTACHED (DONT LIGHT IT) WILL FIND A LEAK.TURN ON THE GAS AND RUN THE HOSE AROUND THE INTAKE,BASE OF CARB OR TBI AND ALONG ANY VACUME HOSE . WHEN A LEAK IS DETECTED THE ENGINE RPMS WILL RISE AS THE GAS IS SUCKED IN THE ENGINE