Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Chevrolet > Blazer > 1969 - 1994 Full size
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 07-29-2013, 07:56 PM   #1
Blind7125
AF Newbie
 
Join Date: Jan 2013
Location: Rockwall, Texas
Posts: 6
Thanks: 1
Thanked 0 Times in 0 Posts
93 Jimmy decelerates after 30ish minutes of driving.

So, about 5 weeks or so ago I moved from Texas to Arizona and was of course pulling a trailer with my 4x4 93 jimmy. About 1/3 of the way through I let my girlfriend take over so I could rest for an hour or so. Well, my nap wasn't quite an hour because I was awoken to her shaking me and saying that the the truck would lose power even with her foot on the gas. Trying to imitate the sound via text is hard but it sounded much like this mmmmmmmmmmmmm..............mmmmmmmmmmmmmm......... ....mmmmmmmmmmmmmmmmm........mmmmmmmmmmmmm. The "mmm" being the hum of the engine like normal. When the silence happened you could feel a sharp decrease in power and I told her to pull over. It felt like the transmission but on further inspection the sound was a misfire. Long story short she had the parking brake on for an hour and driven it for a bit. I took the parking brake off and the drive went flawless. Now, I got to town, moved in, started working, and all was well for a week. Well after a week it started to misfire again after about 30 minutes of driving and I would need to pull over and let the car sit for an hour or two before driving again. No engine lights come on, but I tested the alternator and found it to be faulty so I replaced it as well as a fouled spark plug. The truck ran great for two weeks after that repair until today when it happened again (not nearly as bad but it still happened.)

Things of note:

1. The muffler is completely blown on the bottom side towards the back where it should be welded to the back rim (about 8 inch crack.) The rim/ridge I am talking about is the lip on the left and right sides of this picture: https://encrypted-tbn3.gstatic.com/i...JMIR6RM97S-hTw

2. As stated above the alternator has been replaced

3. The transmission is a year old

4. There is an actuator to the right of the alternator that has a cable going under the cab and two rubber hoses. One big and one small, I noticed last week that both hoses were popped off so I naturally re-attached them. The big hose goes god knows where and the small one attaches to the black ball on the passenger side. The small one was popped off again today.

I am wondering if I should check the ECM next or if you guys have any input. Thanks.

Edit: Once the misfires begin to happen and the car is given a bit of a rest it is difficult to start. I have to sometimes keep turning it over for 4-5 seconds before it quietly sputters back.
Blind7125 is offline   Reply With Quote
Old 07-30-2013, 10:15 AM   #2
maxwedge
A990 racer
 
Join Date: Mar 2002
Location: Chestertown, New York
Posts: 16,946
Thanks: 25
Thanked 369 Times in 363 Posts
Re: 93 Jimmy decelerates after 30ish minutes of driving.

Start by checking fuel pressure, is this throttle body or Vortec, if Vortec there is a port on the fuel line under the hood, you need 60 psi minimum. TB is 10-13 pisi and is more difficult to check, you need adapters at the fuel filter location, which by the way could also be clogged, bad cat could also do this. Now way to really diagnose this over the net without proper testing and equipment.
__________________
maxwedge is offline   Reply With Quote
Old 07-31-2013, 01:36 PM   #3
Blind7125
AF Newbie
Thread starter
 
Join Date: Jan 2013
Location: Rockwall, Texas
Posts: 6
Thanks: 1
Thanked 0 Times in 0 Posts
Re: 93 Jimmy decelerates after 30ish minutes of driving.

It is the 4.3 Vortec. I will check that but it needs to start misfiring before I can get a reliable check. I also noticed yesterday that the drive selector being laid out in the P R N OD D 2 1 is incorrect. I was going through the gears yesterday and it wouldn't lock into first when I slammed it down there. "2" it would shift and D it would lock into as well as shifting up and down OD. Well when screwing around with it my hand slipped and went too far above OD and supposedly into N, but to my surprise the selector locked in and the car kept shifting. Long story short. P is park, little bit before is N is neutral. On N is OD. OD is now D, D is now 2, and 2 is now 1. Truck felt great to drive in the supposed N but it wasn't long enough to check for the misfiring.
Blind7125 is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD

Go Back   Automotive Forums .com Car Chat > Chevrolet > Blazer > 1969 - 1994 Full size

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:18 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts