97 Chevy C1500 idles great, runs rough when put in gear
Asked by JohnyD Dec 27, 2014 at 02:34 PM about the 1997 Chevrolet C/K 1500 Cheyenne Stepside 4WD
Question type: Maintenance & Repair
I've got a '97 C1500 that's been running great for me for the past 6 months. Just the other
day I drove it down to my folks place and when I pulled in the driveway the engine started
running rough.
I let it cool down and tested it again. It starts fine and idles very smooth. Even if I rev it up
to 3 or 4 grand, and still, it runs very smooth. IF, however, I put it in gear it starts idling
very rough. It doesn't stall but if I actually drive it there is a very distinct lack of power. So
much so that it has a hard time getting out of 1st gear. I haven't taken it out on the road to
see if it smoothes out at higher speeds.
I replaced the plug wires a few weeks ago so I double-checked them all and they seem
fine. I pulled the air intake off to see if there was any difference (I'm not certain if the IAC
or MAF sensors can be bypassed in this way or not) but there was not. Didn't seem to
matter.
I don't believe the plugs are all that new.. but the way it runs so great out of gear makes
me feel as though it wouldn't be plugs. Does that make sense? Wouldn't a bad plug make
it idle rough both in and out of gear?... and not just *in* gear?
I'm pretty green with fixing trucks.... but I'm pretty excited with what I've learned thus far.
Any help is greatly appreciated. Thanks.
12 Answers
mikeatpriestlake answered 9 years ago
start by checking the computer for codes. lots of major auto parts stores will do this for free. this may give you your answer, also check for vacuum leaks.
mikeatpriestlake answered 9 years ago
yes, also, a tune up could help, could also be a fuel pressure problem. maybe egr. but egr should throw a code.
No codes are registered, no CEP light. My buddy has a code-reader which I have access to.
migration_skinnerste... answered 9 years ago
Fuel pump is goin bad change fuel filter first its rite under driver side door on frame rail its easy but had same problem bout a month ago another thing the older they get u cant fill the gas tank or the same thing will happen again
Wouldn't a vacuum leak cause performance issue when throttling the truck in park / neutral as well as when in gear?
migration_skinnerste... answered 9 years ago
Filter dont work the pump will go soon nd sometimes faster than u want could b a egrvaulve u cac buy pass it by putting a screw in the intake side of the vacume line if that dont work allmost pos its the fuel pump goin bad
migration_skinnerste... answered 9 years ago
Yes could b vac prob just went through the same shit changed eberything nd was fuel pump but dont rule out your vac makesure u chech bfore u start spending a fortune
I replaced the fuel filter and it didn't make a difference. The old one looked pretty clean too so it may have been replaced recently. I picked up a vacuum guage.... However when I got home it turned out to be a compression guage. *sigh* However, when I picked up the guage I also picked up a distributor cap. I pulled the old one of (which looked pretty new from above) but turned our to be corroded to crap! The the new DP on and it ran like a champ. I bought this truck for 1000$ because the owner thought it was on deaths door. Turns out it's only in purgatory!!! Lotsa life left (fingers crossed!)! Thanks everyone for the advice. It all pushed me in the right direction.
LocalRipper answered 7 years ago
DP is a trick move in group bed-gymnastics.
Check your clutch to see if anything there has gone haywire.
