Heir Apparent
Probationary Member
- 1
- 1
- Sep 25, 2013
-
Susquehanna,
Pennsylvania
Hey everyone. I've been lurking here ever since I picked up my '99 DSM, finally made an account due to an issue I've been having. I see a lot of threads on this issue but most of them either don't get marked as resolved so I never know what works, or else it's an issue I've already checked out. Seems to be one of those problems that's hard to diagnose.
Car: '99 GS, 420A non-turbo.
Symptoms: Rough idle, running rich, gas mileage has gone from 33-35 to 28-29 at best. First world problems, I know. No CEL.
Car idles around 1100-1200 when first started, takes awhile to dip down to normal and when it does, it bounces between 750-950 and sometimes higher. Never wants to stall when idling or when the clutch is pushed in, but it causes noticeable movement in the car when you're sitting.
Seems to run fine otherwise, except for getting too much fuel. The smell is very noticeable when you're sitting with the windows down.
What I've tried so far:
- Compression tested, all cylinders are well in the normal range. PHEW.
- Plugs, wires, and coil pack all changed, plugs gapped correctly.
- Throttle body cleaned out. Was pretty packed with crap.
- Air intake sensor on the throttle body, unsure if that's what it's called, changed.
- Pulled the TPS while idling, revved much higher but still surged a bit. We have a new TPS just in case.
- MAP sensor tested normal.
- PCV valve tested normal.
- EGR valve cleaned and checks out.
- Vacuum lines repeatedly checked, changed a couple, seem okay now.
- New timing belt, timing rechecked just to be safe. Checks out.
- New water pump installed (not really related, but changed with timing belt anyway).
- Top radiator hose was collapsing on repeated occasions after the car was ran, new radiator cap was installed since the other was kinda crap. Unsure if this is resolved as of yet.
- Valve cover gasket was changed. The head was very, very clean for being a '99 with over 100K that had sat for quite awhile. Suspiciously so.
- O2 sensor changed after throwing a code.
Transmission has also been changed to a Neon tranny since the Mitsu had a dying input shaft bearing.
I think that's about it. None of the fixes have worked so far and I'm not confident that the TPS will help either. I plan on swapping out the plugs and wires and also giving the vacuum hoses another good check.
I haven't checked anything to do with the fuel system yet, but if the TPS didn't help and the vacuum lines and plugs/wires were good, injectors were going to be the next thing to look at. Should I redirect my attention to the fuel pump/lines/filter instead?
Pretty stumped here, and any help would be much appreciated. Thanks a lot.
Car: '99 GS, 420A non-turbo.
Symptoms: Rough idle, running rich, gas mileage has gone from 33-35 to 28-29 at best. First world problems, I know. No CEL.
Car idles around 1100-1200 when first started, takes awhile to dip down to normal and when it does, it bounces between 750-950 and sometimes higher. Never wants to stall when idling or when the clutch is pushed in, but it causes noticeable movement in the car when you're sitting.
Seems to run fine otherwise, except for getting too much fuel. The smell is very noticeable when you're sitting with the windows down.
What I've tried so far:
- Compression tested, all cylinders are well in the normal range. PHEW.
- Plugs, wires, and coil pack all changed, plugs gapped correctly.
- Throttle body cleaned out. Was pretty packed with crap.
- Air intake sensor on the throttle body, unsure if that's what it's called, changed.
- Pulled the TPS while idling, revved much higher but still surged a bit. We have a new TPS just in case.
- MAP sensor tested normal.
- PCV valve tested normal.
- EGR valve cleaned and checks out.
- Vacuum lines repeatedly checked, changed a couple, seem okay now.
- New timing belt, timing rechecked just to be safe. Checks out.
- New water pump installed (not really related, but changed with timing belt anyway).
- Top radiator hose was collapsing on repeated occasions after the car was ran, new radiator cap was installed since the other was kinda crap. Unsure if this is resolved as of yet.
- Valve cover gasket was changed. The head was very, very clean for being a '99 with over 100K that had sat for quite awhile. Suspiciously so.
- O2 sensor changed after throwing a code.
Transmission has also been changed to a Neon tranny since the Mitsu had a dying input shaft bearing.
I think that's about it. None of the fixes have worked so far and I'm not confident that the TPS will help either. I plan on swapping out the plugs and wires and also giving the vacuum hoses another good check.
I haven't checked anything to do with the fuel system yet, but if the TPS didn't help and the vacuum lines and plugs/wires were good, injectors were going to be the next thing to look at. Should I redirect my attention to the fuel pump/lines/filter instead?
Pretty stumped here, and any help would be much appreciated. Thanks a lot.
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