HELP! I pulled the car out of storage after 6 years..put some parts on it and it's been reliable for the last 500 miles. Today it would just continue to crank unless you put the pedal on the floor then it would start...5.7 TPI (87 GTA). It would idle around 1k instead of the usual 600 like it has the last few days. Then when I put it into gear it would die. If I pop the gas when I put it in gear it would rev up to around 1200 and then come back to 1k and run fine. I'm not sure if I have one problem or 3. This problem happened hot and cold and went away hot and cold..I backed up the idle screw on the TB but I haven't messed with the IAC yet...I hate intermittent.

It's all or nothing...it either starts and run fines or I get all 3 symptoms....however, I think I have the idle fixed...I'm going to recheck the timing in the morning

Does anyone have any ideas? I unhooked the battery for 10 min...then fired it up and let it run for 30 min....shut it down and restarted...both times it ran fine....I'm so lost..I guess I'll just carry my cellphone and the number to a tow truck.

I've tried it every hour the last three hours and no issues...any jedi's out there have any ideas?

Here's the latest. After you shut it off if you try to immediately restart it you have to hold the gas pedal on the floor to get it to start like it's flooded. It idles anywhere from 1k-1500 when it does start and never goes closed loop. If you immediately put it in gear after starting it dies...if you wait a couple minutes it doesn't but idles at 800 in gear. I am leaning toward a leaky injector or CTS...help...I have to commute in this car in 7 days. Fuel pressure is coming up with the pump but appeared to drop down,,,,could have been a faulty gauge though (it was leaking). Maintains fuel press while the engine's running

Sounds like it could be a maladjusted or bad tps, have you checked it yet?

I'll check that today. THX. There is no black smoke either.

Adjusted the TPS..was .49 now .54 Started after about 5 seconds and idled great. Brought on the check engine light and threw a code 15 for bad coolant sensor...I was able to pull this same code the other day but couldn't get it to duplicate. Tonight I reset the inline plug for the codes....restarted it and got it again...then unhooked the battery for 15 min and restarted...now no codes, no check engine light, and the idle problem is back..i reconfirmed that it's still .54 on the TPS...what'd I do to go backwards? HELP...I was so close..I'm replacing the coolant temp sensor tomorow...but why is it idling high again. I forgot to add I did have to hold the gas on the floor when i started it after resetting the battery....so I do believe the CTS is bad..plus it's very rich. No black smoke though

If youre getting a 15, even if its intermittent, replacing the cts should be the next step, see where you are after that. Your tps looks like it was close enough to spec where it wouldnt have been causing it but atleast you can eliminate it as a possibility.

Thats about all you can do without a scan tool to see what your sensors are doing, jsut start testing and adjusting the more likely and easier things until you narrow it down. That code 15 makes your cts by far the most likely candidate at this point.

I'll replace it tomorow morning and report back..what should happen if you unplug the TPS while it's idling? I unplug it and there is no change. Same with the IAC.

Unplugging the iac just stops the ecm from adjusting it so it would just stay at whatever steps it was at when you unplugged it, in other words unplugging it at idle wouldnt really cause a change or diagnose anything.

As for unplugging the tps, I would assume you would just get a code for it (I dont have my service manual in front of me so I cant check it for sure) but it shouldnt cause any changes on idle either, it would affect it if you tried to drive though. The only reason the tps would have been an issue in the first place is if it was way out of adjustment, like if it was sending 3v at idle, leading the computer to fuel the car like you were at 75% throttle.

The only sensor you can really diagnose by unplugging it is the map, which you dont have. Everything else is checking voltages or disconnecting vacuum lines from things like the fpr to check for diaphram leaks or the charcoal canister to check if it's affecting anything.

Speaking of that, you may as well check it (charcoal canister). You can just unplug the line going from it to the throttle body and see if that affects its running condition. Do remember this would introduce a vacuum leak so you need to put your thumb (or something else that will not get sucked into it) over it (the hose or the tb hole, wherever you disconnect it).

Current status...I had to start the car to back it part way out of the garage..fired right up but still idled high...had to start it again to check the vacuum line and had to put my foot on the floor to get it started. Checked the vacuum line...idle increased when I didn't have my finger over the end of the hose then went back to its normal high idle (1100) when I put my finger back on...getting ready to change the CTS now.

Ya thats normal. what youre looking for is if the car runs better when its not connected to the charcoal canister. The condition would be that the charcoal canister is full of gas and instead of sucking gas fumes into the engine through that line, its sucking actual fuel in and causing drivability issues.

Just stick with the cts for now and go from there if that doesnt fix it .

Taking a beer break...old sensor is broke loose..how much coolant do i need to drain before pulling it out?

just do it real fast, use a towl. no teflon tape . but when you start the ride up again. leave the coolant cap off to bleed the system of any air then add coolant to level close when hot. peace also theres three coolant sensors. how many wires. on the front, left, or right side of block?

I'm changing the one on the front of the block...5.7 TPI..it's the only one. two wire

I got everything back together then had to run my 8 y/o to the hospital for stitches in his lip...indoor tag with his brother . I didn't have time to crank it up and check it all out so I'll fire it up in the morning. I hope that's the fix.

Started it up this morning and fired right up...then shut it off after a minute and refired it twice more. No problems...idles great. No more flooding or high idle...then drove it for 30 min to reset the computer. It appears it was the CTS. I also got rid of the squeel from the alternator belt since I had to retighten it during install. Thanks to everyone for their help.