1999 Chevy Blazer starting and RPM problem

Tiny
KEVIN RINGUETTE
  • MEMBER
  • 1999 CHEVROLET BLAZER
Engine Performance problem
1999 Chevy Blazer 6 cyl Four Wheel Drive Automatic

About 2 weeks ago the blazer started to to take longer to start up. It used to start right up. Now it takes a few seconds for it to finally start up. Sometimes it will start right up with no problem but 80% percent of the time it takes longer to start. Sometimes I have to stop and try a second time and them it will start up. About 5 days after this started to happen I noticed a problem with the RPM's. After I would start it up I would put it into gear and the Blazer would take off on it's own without me pressing the gas. If I let it go on it's own it will go up to about 30 mph and the RPM will stay around 1200 rpm's. The only way I can make the rpm's go back down is I have to press on the brakes until the rpm's drop below 1200 and then it's fine and the rpm's drop to about 6,000. But if I press on the gas and bring the rpm's above 1200 and then take my foot off the gas pedal the rpm's will come to 1200 and stay there and it will keep going by itself until I press on the brakes and make the rpm's drop below 1200 and then the rpm's will drop to the normal idling rpm. I don't care for this because if your not paying attention when you put it into gear and as soon as you take your foot of the brakes it will take off by itself. Seeing that both of these problems with the RPm and the longer starting started pretty much around the same time could what ever is wrong be causing these two problems. Any help with these two problems would be greatly appreciated. Also I replaced the fuel pump 5 months ago and replaced the spark plugs and air filter at the same time. Also the check engine light does not come on and I have a scanner to check for codes and there are no fault codes at all.
Do you
have the same problem?
Yes
No
Saturday, March 27th, 2010 AT 2:56 AM

6 Replies

Tiny
BLUELIGHTNIN6
  • EXPERT
A high idle issue like this is most commonly caused by one of 2 things, either a vacuum leak or faulty / dirty idle air control (IAC) valve. Should start diagnosis by checking for vacuum leaks, sticking throttle plates, faulty PCV valve or restriction in the air induction system.
Was this
answer
helpful?
Yes
No
Monday, March 29th, 2010 AT 3:46 PM
Tiny
KEVIN RINGUETTE
  • MEMBER
Would these things also cause the longer starting. The blazer used to start right away but now it takes a few seconds to start up. The strange part is that sometimes it will start right up. But 80% of the time it takes a few seconds to start. This also started to happen around the same time the idleing problem started. Or would a longer starting time be caused by something else. Thanks for your help. I will start checking the things you said to check.
Was this
answer
helpful?
Yes
No
Monday, March 29th, 2010 AT 5:44 PM
Tiny
BLUELIGHTNIN6
  • EXPERT
It is a possibility that they are connected. Does it restart good? Is the prolonged starting mainly during the first start up or is it just about every time?
Was this
answer
helpful?
Yes
No
Monday, March 29th, 2010 AT 5:48 PM
Tiny
KEVIN RINGUETTE
  • MEMBER
The longer starting problem usually happens when I first start it up or after I let it sit for a while and the engine is cold when I start it. When the engine is hot it pretty much will start right up everytime. But I have gone out a couple mornings or when the engine is cold and it has started right up with no problem. That's the part I don't understand.
Was this
answer
helpful?
Yes
No
Monday, March 29th, 2010 AT 6:09 PM
Tiny
BLUELIGHTNIN6
  • EXPERT
Seems like you may have a fuel pressure issue, perhaps dirty fuel lines / injectors. May want to do a fuel pressure test to see if its getting proper pressure.
Was this
answer
helpful?
Yes
No
Monday, March 29th, 2010 AT 6:35 PM
Tiny
KEVIN RINGUETTE
  • MEMBER
I got a fuel pressure tester and a vacuum pressure gauge and hand pump so I could pressurize the system and a Haynes book to see what the fuel pressures should be and how to test the vacuum and the fuel pressures were all perfect and the vacuum test was also good. I replaced the fuel pump 5 months ago. I also took apart the IAC and cleaned it all out with carb cleaner. The IAC was pretty clean when I took it out. The Haynes book also said to check ohm's On the IAC and It showed what terminals to check and it gave a range of what the ohm reading should be in between and the reading I got were good. Anew PCV valve was cheap so I got a new one. I also cleaned the throttle plates. After doing all that I started the blazer up and the idle problem is still there and it still takes a few seconds to start up. After all I did I would have thought it would have cured at least one of the problems but it didn't. Also one other thing that I forgot to mention is that my wife told me that she has been putting more gas in than blazer than normal. Normaly it will get around 20 to 21 mpg and my wife does mostly highway driving with it so on sunday we went for a trip to the coast and after I we got home I filled it up and did the math and we are now getting 11 mpg. After she went to work on mon and tues and some local driving she did 123 miles with the blazer and I went and filled it up and it took 10.7 gallons of gas. I have never seen it use that much gas and we purchased the blazer new in 99. That came out to roughly 11.5 mpg. Something is definetly wrong. The engine has 81,472 miles on it and most of that has been highway miles and it runs great. Do you have any other ideas as to what I could be causing these problems. You would think the check engine light would come on and give a code but I keep scanning the computer and It has no fault codes at all.
Was this
answer
helpful?
Yes
No
Wednesday, March 31st, 2010 AT 1:32 AM

Please login or register to post a reply.

Recommended Guides