gzilla45 Posted December 1, 2010 Report Share Posted December 1, 2010 When I start my truck in cold weather, typically less than 10 degrees, the throttle tends to stick open about 2500-3000 rpms. The colder it is outside the longer it stays open sometimes upwards of a minute. It is a 97 Ford Ranger 4.0 V6 with about 145k on it. I never have any problems with it starting other than during times of extreme cold. Any suggestions? Unfortunately I wasn't blessed with any mechanical skills so I'm lost when it comes to things like this. Quote Link to comment Share on other sites More sharing options...
LETMGROW Posted December 1, 2010 Report Share Posted December 1, 2010 The throttle should not be sticking open unless you have pushed on the gas pedal to start it. [ Not recommended on fuel injected engines ] More than likely the idle air control has some debris on it and sticks until the heat from the engine loosens it. Another problem these engines often have is faulty coolant temperature sensors. Yours could be telling the computer the engine hasn't warmed yet and the computer is setting the idle up to prevent stalling. This can be monitored with the data screen on a scan tool. The cts can be out of range quite a bit before the computer senses it and turns on the check engine light. Be sure the cooling system is filled to capacity. The cts depends on coolant contacting it to provide an accurate reading. The IAC can be removed and cleaned. I recommend using a spray choke cleaner as it has some lubricating qualities unlike brake cleaner which will dry out entirely. Lynn Quote Link to comment Share on other sites More sharing options...
Shaun_300 Posted December 1, 2010 Report Share Posted December 1, 2010 I agree with Lynn 100%. Probably the IAC valve sticking in the cold. Take it out and clean it and put it back in. Should fix it! Quote Link to comment Share on other sites More sharing options...
gzilla45 Posted December 2, 2010 Author Report Share Posted December 2, 2010 Appreciate the advice. I'll give it a shot. Quote Link to comment Share on other sites More sharing options...
NiteRunner Posted December 2, 2010 Report Share Posted December 2, 2010 Like Letmgrow said, I had a problem with my truck recently that was shooting the rpms out of control and would not allow the truck to start up normally if it was shut off for only a short time. Brought it to the mechanic and here there was a bad part that was telling the computer in my truck that it was -40 degrees out and it needed more gas to keep running. All better now and cost me $90. Quote Link to comment Share on other sites More sharing options...
Shaun_300 Posted December 4, 2010 Report Share Posted December 4, 2010 Like Letmgrow said, I had a problem with my truck recently that was shooting the rpms out of control and would not allow the truck to start up normally if it was shut off for only a short time. Brought it to the mechanic and here there was a bad part that was telling the computer in my truck that it was -40 degrees out and it needed more gas to keep running. All better now and cost me $90. That's the IAT (intake air temperature sensor). When that goes open it defaults to -40. The ECM will do all sorts of wacko stuff to keep the engine running because it thinks it's -40 outside, it also ups the transmission pressures to max, when you put it in gear it comes in nearly hard enough to break the tires loose. And a few other things. This one usually sets an SES light. IAC (idle air control) can, but usually doesn't set the SES light. Quote Link to comment Share on other sites More sharing options...
LETMGROW Posted December 4, 2010 Report Share Posted December 4, 2010 The other part I was refering to was the CTS or coolant Temperature sensor. This is a very common problem on the 4.0, or Ford in general. If you find this part is bad, DO NOT replace it with a plastic based part. They are JUNK! The part from Ford is not priced out of line with aftermarket parts and are much more reliable. A scan tool should show this info on a data screen check. Lynn Quote Link to comment Share on other sites More sharing options...
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