jpawela Posted August 24, 2008 Share Posted August 24, 2008 (edited) I wanted to check with you guys to see if this is normal. I know the VG30 engines aren't anything to brag about and that many owners complain about lack of power in stock form. I do think mine is a bit severe. Basically, my poor truck REALLY struggles to maintain speed on the highway. I can't stay with traffic even on the gentlest of hills and if I happen to be driving into a head wind, the tranny almost never locks up the torque converter and sometimes will downshift into 3rd and I have to keep the throttle at 3/4 of the way open. (This is at 65mph) I noticed today when I was coasting down a 6% grade, the truck still slows down by itself. It seems like it just doesn't want to go above 45mph in top gear. Do I have some sort of rolling resistence? Clogged exhaust? I'm on a tight budget now and can't spring for Thorley's/cat/exhaust yet. Would throwing a freer-flowing catback exhaust help? I experience all of this with just me on board with no other passengers and no load. It's been like this since I bought the truck a year ago. If I have passengers and run the A/C, I pretty much have to leave the O/D off. I don't like the tranny downshifting/upshifting all the time to maintain a steady speed. It seems pathetic. Otherwise the truck's running fine. Idles smooth, revs smooth. It's stock with 105K (timing belt just changed with no effect on power), auto tranny and 31x10.5 tires. I noticed a bad lack of power before upgrading to bigger tires, they just made it worse, obviously. Appreciate any response Edited August 24, 2008 by jpawela Link to comment Share on other sites More sharing options...
MY1PATH Posted August 24, 2008 Share Posted August 24, 2008 My 89XE came stock with 31x10.50 and thats whats been run on it for the past 18 years or so. The 1st gens are somwhat lacking in power but I think yours sounds little extreme. I drove my friends 93se automatic once and it seemd to be more lacking than mine I assume is had issues because I can't imagine the A/T would be that much slower. Anyway I cannot pinpont the issue for you but If you are thinking about exhaust mods there is a wealth of magnaflow cats on ebay for cheap right now (about $80) Search part # "22760" in ebay motors It may come up listed for another vehcle but it will bolt up to yours. borla makes a catback exhaust that also bolts right up or you could have a muffler shop swap your factory muffler for a higer flowing muffler (i prefer magnaflow) for about 150 out the door. those things will help but before all that I reccomend a good tune that includes chainging your cap, rotor, pugs and wires. a worn cap and rotor can cut the power of your spark down dramatically and thus weaken performance and the rest just promotes good couductivity. If that hasnt been done in a while you could likely restore 10 hp hope this helped Link to comment Share on other sites More sharing options...
91PathSE Posted August 24, 2008 Share Posted August 24, 2008 Mine does that...at 75-70 on the highway if you even attempt to accelerate a little bit it downshifts...Im running 31x10.5 tires..and have resistance from lights on top...and I carry all my trail gear all the time...just added weight. Link to comment Share on other sites More sharing options...
yozsi Posted August 24, 2008 Share Posted August 24, 2008 yes, check the cat to see if it clogged/ melted. also you SURE the timing belt was installed correctly? retarded one tooth can severely affect performance. have you checked the ignition timing? Link to comment Share on other sites More sharing options...
adamzan Posted August 24, 2008 Share Posted August 24, 2008 (edited) I wanted to check with you guys to see if this is normal. I know the VG30 engines aren't anything to brag about and that many owners complain about lack of power in stock form. I do think mine is a bit severe. Basically, my poor truck REALLY struggles to maintain speed on the highway. I can't stay with traffic even on the gentlest of hills and if I happen to be driving into a head wind, the tranny almost never locks up the torque converter and sometimes will downshift into 3rd and I have to keep the throttle at 3/4 of the way open. (This is at 65mph) I noticed today when I was coasting down a 6% grade, the truck still slows down by itself. It seems like it just doesn't want to go above 45mph in top gear. Do I have some sort of rolling resistence? Clogged exhaust? I'm on a tight budget now and can't spring for Thorley's/cat/exhaust yet. Would throwing a freer-flowing catback exhaust help? I experience all of this with just me on board with no other passengers and no load. It's been like this since I bought the truck a year ago. If I have passengers and run the A/C, I pretty much have to leave the O/D off. I don't like the tranny downshifting/upshifting all the time to maintain a steady speed. It seems pathetic. Otherwise the truck's running fine. Idles smooth, revs smooth. It's stock with 105K (timing belt just changed with no effect on power), auto tranny and 31x10.5 tires. I noticed a bad lack of power before upgrading to bigger tires, they just made it worse, obviously. Appreciate any response Mine was doing this and it turned out that my original cat's were clogged AND my o2 sensor is shot. I have a new cat and still running the old 02 (don't have any cash right now) its a bit sluggish on acceleration but once it is on the highway it'll stay locked in OD. How is your gas mileage? I know these aren't great on gas, but you should get at least 320 miles to a tank. Depends on how you drive though. Unplug your o2 sensor and see if it runs any better. Edited August 24, 2008 by redfinder Link to comment Share on other sites More sharing options...
JoeBob Posted August 24, 2008 Share Posted August 24, 2008 320? :O I get like 250 - 300 when I drive nicely Link to comment Share on other sites More sharing options...
adamzan Posted August 24, 2008 Share Posted August 24, 2008 Then again my truck is completly stock. Don't know about jpawela Link to comment Share on other sites More sharing options...
jpawela Posted August 24, 2008 Author Share Posted August 24, 2008 Yup, I'm bone stock. I'll give that a shot. Gas mileage is fine: I'll get around 19-20mpg on the highway. Thanks and also thanks to everyone else for the comments. Link to comment Share on other sites More sharing options...
jpawela Posted August 24, 2008 Author Share Posted August 24, 2008 If my cat is clogged, wouldn't that through a code or make it run all @!*%ty? Link to comment Share on other sites More sharing options...
MY1PATH Posted August 25, 2008 Share Posted August 25, 2008 Mine does that...at 75-70 on the highway if you even attempt to accelerate a little bit it downshifts...Im running 31x10.5 tires..and have resistance from lights on top...and I carry all my trail gear all the time...just added weight. I think that sounds about right. mine felt pretty pathetic gettin above 80 before I did my full exhaust. still feels weak up there but not near as bad. and 300ish to a tank sounds about right. I usually fill @ about 1/2 tank and lookin' 140-160 (depending on if most those miles were super slow military base speeds or higway/normal town driving) Link to comment Share on other sites More sharing options...
jpawela Posted August 28, 2008 Author Share Posted August 28, 2008 Hey, do the wd21 pathy's have two cats or just one. I think I'll spring for that higher-flow cat by magnaflow. Just wanted to make sure. Link to comment Share on other sites More sharing options...
91PathSE Posted August 28, 2008 Share Posted August 28, 2008 Just one Link to comment Share on other sites More sharing options...
Simon Posted August 28, 2008 Share Posted August 28, 2008 some Cali emissions models had a pre-cat as well. Totally useless, and unnecessary. I had mine removed when my exhaust was done, and my truck passed emissions without issue. Link to comment Share on other sites More sharing options...
Legalalien Posted August 28, 2008 Share Posted August 28, 2008 If you still have the auto hubs you might want to check that they are not locked on. Link to comment Share on other sites More sharing options...
Red87Path Posted August 29, 2008 Share Posted August 29, 2008 what exactly happens when you unplug your o2 sensor, i unplugged mine once because of idle issues, hasnt ran right since, i replaced it, my cat, my maf , checked and double checked timing checked and rechecked all vacuum lines even as far as pulling them all off and plugging them and blowing through them to see if there were any leaks, nothing. pulled my throttle body off, cleaned and put new gaskets on it. pulled the egr valve off and checked to see if it or the tubes were carboned up. checked compression, checked injectors, unplugging one and let it run , then switch to the other. but it all goes back to unplugging my o2 sensor that one time. mine has no power, idles great, revs great, wont accelerate. spits and sputters like only firing on half the engine. getting spark through all wires. dont know if it is strong enough spark though, not sure what it should look like. anyone out there with the z24i? im wondering if distributor is in right. the plug for the crank sensor is in front, facing the radiator, wondering if it is supposed to be facing firewall. seems to make more sense the way the wiring runs for it to face the other way. also, how much slop is acceptable in the dizzy drive gear, have a bout a 1/4 inch of wiggle in mine. i could really use a miracle here. Link to comment Share on other sites More sharing options...
pathy95 Posted September 8, 2008 Share Posted September 8, 2008 I noticed today when I was coasting down a 6% grade, the truck still slows down by itself. It seems like it just doesn't want to go above 45mph in top gear. is it possable that you might have a brake sticking Link to comment Share on other sites More sharing options...
MY1PATH Posted September 8, 2008 Share Posted September 8, 2008 rolling down a hill in neutral and with the aerodynmic profile of a brick my pathy will still maintain 60ish untill the ground flattens out Link to comment Share on other sites More sharing options...
jpawela Posted September 9, 2008 Author Share Posted September 9, 2008 is it possable that you might have a brake sticking brakes actually do need attention. especially the front where they clunk and squeak like hell. Link to comment Share on other sites More sharing options...
Precise1 Posted September 9, 2008 Share Posted September 9, 2008 Honestly, it sounds like a combination of things, not just 1. Yes, these are not powerful trucks, but generally have enough power to maintain. I'd advise checking any drag points, ie brakes and wheel bearings. How is the tranny fluid? Is there a tranny issue perhaps? From there I'd run the ECU codes just for luck, check/clean the MAF, dizzy and then look towards the exhaust. As has been said, a clogged cat can kill performance but won't necessarily throw a code... B Link to comment Share on other sites More sharing options...
adamzan Posted September 9, 2008 Share Posted September 9, 2008 What B said, also, does it sometimes just run really sh!tty at idle and put a bit of black smoke out the tail pipe? As if you were pressing on the egr valve. Mine did that when the cats were clogged. Link to comment Share on other sites More sharing options...
jpawela Posted September 14, 2008 Author Share Posted September 14, 2008 Well I had the brakes adjusted and the front pads replaced. Didn't change a thing. Is there an easy way to check ignition timing without consulting a mechanic? Link to comment Share on other sites More sharing options...
Precise1 Posted September 15, 2008 Share Posted September 15, 2008 You need a timing light, other than that, it is simple. Just clip on the leads and shine the strobe down at the crank pulley slightly off to the passenger side. Mind the fan blades though!! It's best to check the distributor cap and rotor beforehand... B Link to comment Share on other sites More sharing options...
k9sar Posted September 15, 2008 Share Posted September 15, 2008 and if you're a cheapskate... buy one at walmart... use it... then return it (but keep it clean and nice). Link to comment Share on other sites More sharing options...
jpawela Posted September 15, 2008 Author Share Posted September 15, 2008 ^yup, i'm a cheapskate...might consider that! Link to comment Share on other sites More sharing options...
jpawela Posted October 18, 2008 Author Share Posted October 18, 2008 UPDATE: Well, it's not fixed but I have a sure diagnosis...it's the cat. Mechanic says that it's partially clogged. Timing, compression, drag points were all good. I didn't know a cat could have this kind of effect. Anyway, thanks for all your help fellas! Link to comment Share on other sites More sharing options...
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