Starting to run out of ideas here. I’ve got my ‘98 manual 4.0 (here name is Susan for reference) that is idling high and running really rich. So when I start her up she runs like a top, sits around 800 RPM and drives well until we get up to operating temp. Once’s she’s warm, idle starts to climb. If I have it in the driveway just at idle it will slowly start to creep up once it gets warm and sit between 1500-2000 RPM. When driving it’ll idle at about those RPMs when I’m at a light or stop, but when I shift between gears it’ll skyrocket well past 2000 until I get it in gear (feels like someone stomps the throttle between gears, a little scary to shift between them). I also noticed that she’s been running really rich lately, lots of black soot caked on the exhaust and a D ring on the rear bumper. The exhaust I put on about 4 months ago or so, problems only started to arise maybe a month ago.
I’ve read probably forum on this topic and tried quite a few troubleshooting ideas, so here’s where I’m at:
Checked for any vacuum leaks, unsuccessful in finding any as of yet. The intake and exhaust manifolds (to my knowledge) have never been removed so unless they’ve shaken a bolt loose I think I can rule that out. Throttle body, IAC, MAP port in TB have all been thoroughly cleaned. Battery disconnected and let sit for half an hour and reconnected. New sparks plugs (just plugs, not wires or distributor cap). Maybe a random thing or two that I’m forgetting, as well as acknowledging the fact that cars are pain but I still love my girl dearly.
Next thought would be to replace both upstream O2 sensors. Other than that, I’m pretty stumped. Don’t want to start throwing parts at her, not sure that any of it’s necessary just yet (remains to be seen).
Main confusion is from the fact that she starts and idles fine at first, but once she gets up to temp she gets upset. Any and all suggestions are both welcomed and encouraged, thank you guys so much for the help!!
I’ve read probably forum on this topic and tried quite a few troubleshooting ideas, so here’s where I’m at:
Checked for any vacuum leaks, unsuccessful in finding any as of yet. The intake and exhaust manifolds (to my knowledge) have never been removed so unless they’ve shaken a bolt loose I think I can rule that out. Throttle body, IAC, MAP port in TB have all been thoroughly cleaned. Battery disconnected and let sit for half an hour and reconnected. New sparks plugs (just plugs, not wires or distributor cap). Maybe a random thing or two that I’m forgetting, as well as acknowledging the fact that cars are pain but I still love my girl dearly.
Next thought would be to replace both upstream O2 sensors. Other than that, I’m pretty stumped. Don’t want to start throwing parts at her, not sure that any of it’s necessary just yet (remains to be seen).
Main confusion is from the fact that she starts and idles fine at first, but once she gets up to temp she gets upset. Any and all suggestions are both welcomed and encouraged, thank you guys so much for the help!!
