97 Sputters with no codes. Any ideas?

[Project96]

Hi everyone. My '97 sputters and I'm out of ideas. I hope someone can help. Ok, here's what happened. I drove 70 miles down the interstate. As I slowed down at the bottom of the ramp the car started idling rough like it was overheating. So I stopped down the street where I work and looked at the engine and it was hot and coolant level was fine. Checked both radiator hoses and both were equally hot. Leaving me to think that the thermostat didn't stick shut.
I had to go back to work. I let the car cool down until the next day hoping that the erratic idle from running hot would be gone and would start up and run fine.
It cranked like it didn't want to start. After It started, it wanted to die out and was sputtering the same as when I parked it hot. I checked the codes with my OBDII scanner and no codes came up when the engine was off. However, With the engine running and doing a KOER test, I came up with 3 codes (IAC issue, temp sensor out of test range, and test incomplete). So I started by replacing my IAC with a new one, then everything else trying to fix the problem such as TPS, MAF, Intake air temp sensor, both coolant sensors. All new sensors but still have the same 3 KOER codes.
One thing to note is that the car does not hessitate like a fuel issue when I rev it up. But smells like gas really bad when it is running. I was thinking a misfire but don't have any misfire codes or Coil Over Plug codes. I also checked the IAC passage and it is clean.

I am out of ideas. The only thing I can think of that is left is the PCM. After that, I may have to take it to a dealership and I totally want to avoid them at all costs.

Please let me know if anyone has any ideas. I really really appreciate your guys help. Thank you in advance.

Jason

 

[SHOZ123]

Temp sensor out of range means the car was too hot. This may be due to a bad ECT and it not turning on the fans.

 

[medgraphsho]

Hi everyone. My '97 sputters and I'm out of ideas. I hope someone can help. Ok, here's what happened. I drove 70 miles down the interstate. As I slowed down at the bottom of the ramp the car started idling rough like it was overheating. So I stopped down the street where I work and looked at the engine and it was hot and coolant level was fine. Checked both radiator hoses and both were equally hot. Leaving me to think that the thermostat didn't stick shut.
I had to go back to work. I let the car cool down until the next day hoping that the erratic idle from running hot would be gone and would start up and run fine.
It cranked like it didn't want to start. After It started, it wanted to die out and was sputtering the same as when I parked it hot. I checked the codes with my OBDII scanner and no codes came up when the engine was off. However, With the engine running and doing a KOER test, I came up with 3 codes (IAC issue, temp sensor out of test range, and test incomplete). So I started by replacing my IAC with a new one, then everything else trying to fix the problem such as TPS, MAF, Intake air temp sensor, both coolant sensors. All new sensors but still have the same 3 KOER codes.
One thing to note is that the car does not hessitate like a fuel issue when I rev it up. But smells like gas really bad when it is running. I was thinking a misfire but don't have any misfire codes or Coil Over Plug codes. I also checked the IAC passage and it is clean.

I am out of ideas. The only thing I can think of that is left is the PCM. After that, I may have to take it to a dealership and I totally want to avoid them at all costs.

Please let me know if anyone has any ideas. I really really appreciate your guys help. Thank you in advance.

Jason

If you smell gas, check your fuel pressure and fuel lines... may have a leak somewhere or it could be clogged injector

also check your schrader valve

 

[Project96]

Ok. So the temp sensor code is from before when it got hot. Now I figured the code for test incomplete must be from me disconnecting the battery and not driving after reconnecting it and allowing it to fully diagnose the system. But I still get that IAC code. I checked the engine for fuel leaks. Couldn't find any. I smell the gas from the exhaust. So it must be getting more fuel than normal or not enough air. Again, I get that IAC code which might point towards not enough air.
Now if I have an issue with a faulty fuel pressure regulator or injector like medgraphsho mentioned and letting to much fuel in, would the oxygen sensors think that theres not enough air when theres actually too much fuel?
Would the engine RPM stay low almost causing the car to die if it were getting flooded with fuel or would the RPM's be high because of the increased fuel?

Thanks again

 

[SHOZ123]

To see if the IAC is working unplug it when the car is running. It should die immediately. If it does not then either the IAC is sticking or there is a vacuum leak.

 

[medgraphsho]

check your schrader valve

 

[Project96]

I know its getting fuel. It stays running. I'm thinking it might be getting too much. One thing I forgot to mention is that after I installed a new MAF the car had a tad better idle but not much better. Maybe the new MAF brings a little more air in because its more accurate than the old one. Bringing the air/fuel closer to even.
I'll unplug and replug the IAC tomorrow to see if it has any effect. I'm thinking my fuel pressure regulator is shot and overpressuring the fuel rail. I will put a new regulator in and see if that helps.

Thanks for all your input. I really appreciate it. I will keep you updated on the results.

 

[Project96]

Ok. I unplugged th IAC. She died out right away. So thats working fine. I'll try the fuel regulator later today.

 

[Project96]

Alright. I replaced the fuel pressure regulator. Nothing happened. Upon putting my hand on the intake, I noticed that one of the intake tubes was very hot compared to the other 7. The tube was for a front and second from left cylinder. Previously, i had a very very light tapping noise coming from that cylinder, but thought it might be a valve out of adjustment.

Does anyone have an idea what might be wrong with my valve? There's no backfiring or clunking sound.

Thanks again

 

[SHO U UP]

This may seem like a long shot, but are your cams welded??

 

[SHOZ123]

Pull the plugs from the front and see if the hot cylinder looks different.

 

[1995mtxsho]

This may seem like a long shot, but are your cams welded??

What he said....

Valve tapping and then it running poorly can be a sign of cam failure.

 

[Project96]

I'm not sure if the cams have been welded. I will have to pull the valve cover and check. Now, if the plug in the suspect cylinder is burnt and the rest are fine, would that mean that its a valve issue and not a cam issue? If it is a cam issue, is it possible to remove and fix or replace the cam with a welded one without dropping the motor or extensive engine disassembly. It hasn't made any kind of knocking noise yet so I don't think it has touched a piston. I didn't even notice it when it went. I first noticed it while coming to a stop at an off ramp. So maybe my cam has started walking and is ready to break. I'll pull my plugs and valve cover. Please let me know whats involved with fixing or replacing the front intake cam. Thanks you guys.

 

[1995mtxsho]

The suspect plug will most likely be wet.
Failed cams don't knock, they tick, and you would be hard pressed to 'hear' the valve to piston contact. The ticking is the cam lobe slapping the valve shim because the valve is bent and slightly open.

Fixing the cams will require the whole drive-train/sub-frame to be dropped.
Pulling the front cover is nearly impossible with the engine still in the car.

 

[luigisho]

Pulling the front cover is nearly impossible with the engine still in the car.

What are you talking about? I replaced valve cover seals a few weeks ago with the motor in the car. Tight but doable.

 

[Project96]

Ahhhhh. I see what your saying. Yeah, I guess it would have a bent valve. I guess I'll just pull the motor and keep it for parts and just buy another car and have the cams welded right away.

Again. I thank you for all your input.

 

[1995mtxsho]

What are you talking about? I replaced valve cover seals a few weeks ago with the motor in the car. Tight but doable.

Front cover, as in the front of the engine! Not the valve covers.

Front cover = Timing Chain Cover.

 

[venom]

Ahhhhh. I see what your saying. Yeah, I guess it would have a bent valve. I guess I'll just pull the motor and keep it for parts and just buy another car and have the cams welded right away.

Again. I thank you for all your input.

Bump the starter and see if the water pump pulley near the battery is turning when the engine turns.

If it is not turning you most definately have a failed cam in the front bank. I would think that you would have had misfire codes for each front bank cylinder tho.