1991 Ford Tempo Engine Idle

MMCLUCKIE

MEMBER
1991 FORD TEMPO
4 CYL
FWD
AUTOMATIC
113,000 MILES

My car idle while parked or stopped willl flutuate between 900 and 1100 rpms. It will be 900 and then after about 8 seconds jump to 1100 rpm, and then after another 8 seconds jump back down to 900 rpms while at a stand still. Also, I think I notice while driving a very small burst of power once in awhile without pushing down on the accelerator. I have replaced the fuel filter, cleaned the K and N air filter, cleaned the throtle body insides, replaced the idle air control valve, and done a quick check of vacuum hoses (but not a detailed check). Also, I did check the error codes on my engine. At first check I did get an error code for the EGR valve, but after replacing the IAC valve and clearing the codes it went away. That was a week ago, and I have not checked since. Any ideas?

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Hi mmcluckie, Welcome to 2carpros and TY for the donation

Check the fuel pressure if its within specs if okay clean the mass airflow sensor with an approved cleaner and test the throttle position sensor

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Saturday, May 22nd, 2010 AT 8:32 PM

MMCLUCKIE

MEMBER
2 POSTS

Hello,

I sent in a question with some money about a car with a high idle that would bounce between 900 and 1100 rpm after 8 seconds, back and forth. I was given the advice to change the MAF sensor and check fuel pressure. My car has a MAP sensor and I replaced it. I do not have the tools to check the fuel pressure, but I checked the vacuum pressure and found it to be bouncing between 12 and 15 psi. Any thoughts.

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Saturday, May 29th, 2010 AT 12:17 AM

FIXITMR

MECHANIC
9,990 POSTS

Free help here. I will mention that I was working with a tempo that the fan was not coming on the other day and removed the plug for engine temp sensor instead of fan temp sensor and noticed an immediate drop in idle speed of at least 200 rpm. This shows you it might possibly be a sensor deviation problem? You didn't mention checking the TPS? Use cheap ohmmeter. It should show a mice smooth increase/decrease with no skips or jumps. They are not as expensive as IAC. I'm gonna do a vacuum check on that tempo to see what the gauge says to compare with yours. You could try googling your vacuum results for clues also.

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Saturday, May 29th, 2010 AT 1:38 AM

RASMATAZ

MECHANIC
75,992 POSTS

You didn't get an advise to change the MAF sensor -you were told to clean it which is possible if it has one maybe we'll try the IACV for the fluctuation, could be very well be the TPS sensor Lets try checking the idle and WOT voltages

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Saturday, May 29th, 2010 AT 4:36 AM