Runs Rough When Warm...Ideas?
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 28
Likes: 0
From: Eldersburg Maryland
Runs Rough When Warm...Ideas?
Hi,
I'm looking for some advice on what to try to solve my issue.
I have a 1990, all stock, with ONLY 21,000 miles. Over the last
few months, the car seems to run fun for the first 20min. Then
it starts to run rough...you can feel it most when at idle and in DRIVE,
but you can still tell it is running rough when moving as well.
This weekend, it got to 85 here in Baltimore, and after about 35min,
the car almost just quit while I was going 70mph. I was low on
gas (reserve with only 1 bar on the display), so I was able to
limp it to a gas station. I got gas, the problem was still there. No
power, could barely get it above 25mph. I let it sit for 2-3hrs, it
got me home, but still ran rough. Any ideas on steps to fix this?
Like I said, it is 18yrs old with the original wires/plugs/cap/rotor/etc.
Should I attack there first? What about fuel? New filter? Should
I mess with the idle air bypass stuff?. Being that it is worse when
it heats up, I'm thinking it isn't fuel related.
Any thoughts and ideas would be great. Thanks!
90 White Lightning
I'm looking for some advice on what to try to solve my issue.
I have a 1990, all stock, with ONLY 21,000 miles. Over the last
few months, the car seems to run fun for the first 20min. Then
it starts to run rough...you can feel it most when at idle and in DRIVE,
but you can still tell it is running rough when moving as well.
This weekend, it got to 85 here in Baltimore, and after about 35min,
the car almost just quit while I was going 70mph. I was low on
gas (reserve with only 1 bar on the display), so I was able to
limp it to a gas station. I got gas, the problem was still there. No
power, could barely get it above 25mph. I let it sit for 2-3hrs, it
got me home, but still ran rough. Any ideas on steps to fix this?
Like I said, it is 18yrs old with the original wires/plugs/cap/rotor/etc.
Should I attack there first? What about fuel? New filter? Should
I mess with the idle air bypass stuff?. Being that it is worse when
it heats up, I'm thinking it isn't fuel related.
Any thoughts and ideas would be great. Thanks!
90 White Lightning
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
To cite the obvious: Is it showing any codes? I suspect it is. My knee jerk response is the O2 sensor. First, pull codes. If you can't AutoZone can,a freebie. Get back to us with numbers. Second plan on a complete tune up.
Race Director
Joined: Feb 2002
Posts: 16,105
Likes: 7
From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
I'm having the EXACT same issue with my 91 Trans Am. It's a 305 TPI. I am going to get it looked at in a shop later this week and will let you know what they tell me. I bought it with 159,000 miles on it, it now has 176,000 miles on it and I've never changed any of those and who knows how long it had been before I bought it. I'm guessing that is going to be the problem... but I'm also having them price a 350 for me.... so it may not be fixed on the current motor... 
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 28
Likes: 0
From: Eldersburg Maryland
I just shorted A & B on the diagnostic connector to read out the codes....and I got nothing...It just flashed "1" "2" , the handshaking code, for as long as I waited (10-15 times). So, it is not reading out any codes. So, does this point more to the plugs/wires/cap/rotor, etc.?
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 28
Likes: 0
From: Eldersburg Maryland
Never :>)
You are the second person who suggested changing the fuel filter. I did run some Seafoam through the take back in Dec...It didn't really change anything....
Thanks!
You are the second person who suggested changing the fuel filter. I did run some Seafoam through the take back in Dec...It didn't really change anything....
Thanks!
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
Little surprised there are no codes. My only suggestion is a complete tune up to include a fuel filter. Can you get a scan done? That may tell you bunches if the tune up doesn't do the trick. No codes,how about that.
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. Ohm them and see if their bad. All should be around 16.5 ohms.
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 28
Likes: 0
From: Eldersburg Maryland
Hey...I just ohm'd my injectors...this is what they read....
7.3, 15.5, 16.4, 11.3, 5.1, 2.5, 16.7, and 7.5
I'm guessing that all but about three of them (the 16.4, 16.7, and 15.5) are history???
I'm assuming just go ahead and replace all eight of them, correct?
How hard a job is this?.....It may be more than I want to tackle right now. I may have the mechanic down the street do it.....
7.3, 15.5, 16.4, 11.3, 5.1, 2.5, 16.7, and 7.5
I'm guessing that all but about three of them (the 16.4, 16.7, and 15.5) are history???
I'm assuming just go ahead and replace all eight of them, correct?
How hard a job is this?.....It may be more than I want to tackle right now. I may have the mechanic down the street do it.....
